The only one of those that looks remotely interesting as a PW rtd is the crafting one.
...May I ask why? Speaking as a Tinker addict, and a former Perplexicon player, crafting and complex systems in general are piecewise's weakest area, in my opinion. His skill area is generally eldritch/creepy/creative world stuff. I'm curious why you have the opposite impression.
Actually, even with this said, I'd still rather come to the opposite conclusion - despite Piecewise sometimes missing potential pitfalls, I'd say his crafting and complex systems are some of the most interesting things about his games. This might be because he's willing to go to such lengths in modelling them (allowing for aforementioned pitfalls, but also for a great amount of fun time to be had). So yeah, whatever game idea is chosen, I would very much love if it had (though open to abuse, munchkin heaven, whatever - syv would clearly disagree with me here, I guess) a complex and interesting "crafting" system in the vein of Tinker, Perplexicon magic, etc.
Anyway, what really sounded interesting to me was the Pacific Rim knock-off; not for the general idea, however, but - for something that was apparently not even intended as something of a main game feature - the specific "tag team" implication for players. I'm... not sure that just "having different players control different body parts" would have been as interesting, as I'm not talking about autonomy - but rather having the players clearly work as a team as a
prerequisite (and not as a "desirable, but superfluous" thing as it was in ER). I do recall that at some point PW considered running an urban mecha-tank combat, with a couple of players running each tank - one being the driver, another the gunner, etc. - and while I'm not specifically that interested in that particular setting or game features, I think that central game idea of having players play in complete concert is worth considering. Not as "okay, I'm going north, you're going south, we try to flank it and hopefully one of us would succeed and kill it" - but rather as "my own and others survival depends on actions of each of us; I cannot just act on my own, run away or something - we survive or die as a team", a faithful
crew simulator - be it a crew of a tank, a giant mecha, an airship, a starship, or maybe even a good old sailing ship or something.
(Then again, it may sound awesome to me, but it might be completely unviable as a basis for a forum game. I will defer the judgement to Piecewise himself.)
Edit: Ninja'd by Piecewise himself!
On mentioned ideas: I certainly do like the idea of moving the power level of starting players later in the game to accommodate general power progression of others (and lessen the too great difference between best veterans and completely new characters).
I'm not sure I like the "Limited Skill Trees" idea, though - partly because it seems somewhat hard to balance melee against all ranged options, and partly because I'm not sure it's a good idea to force such a restriction upon players. Still, as a way of creating modular
classes system (and thus sidestepping the problem of coming up with distinct yet balanced classes otherwise), the idea is quite nice and actually very good, I think.