To end the suspense now, I'm not going to solve any major unsolved problems in this post.
As far as I know, there is still no way to have a minyan that is both gender-egalitarian (meaning that people are not classified by gender) and compatible with a version of halacha that requires that prayer leaders be of a particular gender. (Maybe Jews in the Woods will figure it out someday; they haven't yet, but not for lack of trying.)
Contrary to popular belief, minyanim in the style of Shira Hadasha (where men are poreis al shema and oveir lifnei hateivah (i.e. men lead shacharit/musaf/mincha/ma'ariv), and women lead peripheral services such as kabbalat shabbat and pesukei dezimrah, and people can read Torah and have aliyot without regard to gender) do not accomplish this. And generally they don't claim to. These minyanim are meeting a real need for a particular set of people (and, in some cases, providing a sufficiently high-quality prayer experience that people outside that set are willing to compromise their principles and pray there), but they're not providing a permanent solution that will make it possible for everyone to pray together in Stage-3 harmony. And again, they're not claiming to. The reason they don't provide this solution is because they're not actually egalitarian (nor, generally, do they claim to be). The set of public roles that one can have in the community is still prescribed by one's gender. I can't ever lead kabbalat shabbat, my female friend can't ever lead shacharit, and 10 Jewish adults (of whatever gender) can't count themselves as a minyan. Yes, a service led by men and women is better (from the perspective of greater inclusion) than a service led only by men. But it is no more egalitarian. Being "mostly egalitarian" is like being "a little pregnant". That's not to say that these minyanim don't have an important place among all the other types of minyanim. But they are not a Stage-3 solution that includes people who seek to be in a community that is fully egalitarian.
I'm also not going to solve the issue of instruments on Shabbat. A service either uses instruments on Shabbat or it doesn't; I can't think of any other options. Some people attend minyanim like Kol Zimrah, where the leader is playing instruments, even though they personally wouldn't use instruments. But I can see how that wouldn't work for everyone. I suggested a "live and let live" approach in Part II using the example of writing on Shabbat, but I can see how hearing instrumental music as an integral part of the communal prayer that you're participating in would be much more conspicuous and harder to ignore than being in the same room as someone who is writing.
In Stage 1 and Stage 2, some people insist that they "can't" pray or "aren't comfortable" praying in a service where instruments are used on Shabbat. Therefore, it appears that the pluralistic solution is no instruments on Shabbat. The people who want instruments on Shabbat are then backed into a corner, so we respond that we "need" to have instruments in order to pray, and make fools of ourselves in the process. Of course we don't "need" instruments, and shame on Stage-1 discourse for twisting us into making ridiculous statements like that. In limited circumstances, having a Shabbat service/event without instruments is a perfectly reasonable way to accommodate everyone. In Stage 3, the problem arises when looking at the long view. While it may be acceptable for everyone to go without instruments for any one particular instance, it becomes unacceptable (from a Stage-3 identity perspective) if people are forced to never pray with instrumental music. So the best achievable solution is what we already have: pray together (without instruments) some of the time, and pray separately (with and without instruments) some of the time. In my world, this is achieved by attending multiple independent minyanim that meet on different weeks.
That's as good as we can do, but maybe that's not so bad; maybe Stage 3 means having lots of options, and identifying with the big picture, not necessarily identifying with every option.
Now that I've listed the issues that I don't think can be pluralistically solved at the present time, let's start picking the low-hanging fruit.
The trichitza* should have appeared in the Year In Ideas. I'm not being sarcastic. It's an elegant idea that didn't exist, and then someone came up with it, and everyone said "Why didn't I think of that before?"
[Linguistic excursus on the word trichitza: Some have suggested that this word is problematically constructed, because the "tri" means 3, and the "chitza" means "half", so "trichitza" suggests three-halves or one-sixth, when a meaning of one-third is desired. This doesn't bother me, because chatzi can refer to any fraction less than a whole, not necessarily a half, so "trichitza" can still mean "dividing in three". Some have suggested meshlisha as an alternative. This also successfully carries the connotation of "three" while sounding like the source word mechitza. However, as I have discussed elsewhere, it runs into grammatical problems, because a Hebrew word cannot start with two shevas. This problem might be avoided with the word mashlisha, with a patach, which can be understood as a participle of the nonexistent hif'il verb l'hashlish, to divide into thirds. The word meshalesh(et) might also mean the same thing ("something that divides something into thirds"), using a verb form that already exists, but lacks the assonance to mechitza. Finally, some have suggested meshlitza as a hybrid. I don't really understand this one. In addition to the two-sheva problem, a shoresh (particularly one that is shelamim) can't really be split like that; a shoresh is an indivisible morpheme.]
I think the trichitza may have originated at Jews In The Woods, but don't know for sure; can anyone confirm the origin? (Disclaimer: I've never been to JITW, and never been to a minyan with a trichitza.)
The idea is simple: divide the prayer space into three sections, one non-gendered, one women-only, and one men-only. If people want to pray in a space where they are not classified by gender, they can do so, and if they want to pray in a single-gender space for whatever reason (because they believe that this is required by halacha, or because they would be distracted by the presence of the opposite sex, or because they believe in masculine/feminine "energy"), then they can do so. There's something for everyone, and no one is coerced.
The beauty is that it automatically shifts in response to consumer demand: if everyone wants mixed seating, then *poof*, the single-gender sections cease to exist (since no one is sitting there), and if everyone wants separate seating, then *poof*, the mixed section ceases to exist. And if Reuven feels lonely because he's the only person in his section, then, well, he's still getting the best outcome that he can reasonably hope for in the context of that community: the alternatives are either that Reuven prays in a way that he doesn't want to, or the rest of the community is coerced into praying in a way that they don't want to, both of which are suboptimal outcomes. If Reuven's loneliness outweighs his reasons for being in his section, then he can always switch to the other section. And if not, then he can either stay where he is and deal with it (knowing that he is in a community where his choice is respected albeit not shared), or find another community with more like-minded people. Life is about making choices, and taking responsibility for one's choices.
Now that the trichitza idea is out there, there's no going back. Any minyan that has constituents who prefer separate seating and constituents who prefer mixed seating, and that takes no official stance that one of the options is invalid, should have a trichitza. In particular, the minyanim [N.B. not the same as the Shira Hadasha-style minyanim discussed above] that combine egalitarian prayer leadership with separate seating (despite the preferences of many people in their communities for non-gendered seating) have no excuse. They may have started out with separate seating as a "compromise" (hello, Stage 2), but such compromise is unnecessary now that the trichitza option exists. It's possible for these minyanim to move to Stage 3 on this issue if they want to.
It distresses me that some supporters of these minyanim refer to them, tongue in cheek, as "separate but egal". This is no laughing matter. Comparing one's community to Jim Crow segregation should create some serious cognitive dissonance. If one believes that the two situations are analogous (full disclosure: I actually sort of do, and Brown v. Board of Education has taught us that "separate but equal" is inherently unequal) then one should strive to rectify this rather than accepting it cheerfully, and if one believes that they're not analogous, then the comparison to historical hatred and oppression isn't appropriate even as a joke.
Ok, this post has gone on long enough that it's time to publish, and there are lots of prayer-related issues that haven't been touched yet. This post hit some macroscopic prayer issues; Part IV (coming soon) will focus on microscopic prayer issues, such as liturgy. What topics do you want to see in Part V and beyond?