Forum OpenACS Development: Re: "Nice JSP version of ACS 3.4" - Does somebody keep a copy?
Note, what little empirical research I've seen on how software tools become popular doesn't seem to suggest that using PHP rather than Tcl is likely to be that significant. Indeed, my understanding is that Tcl's first and strongest wave of popularity was directly because Tcl/Tk did GUIs far better than anything that had come before. (I haven't read my copy yet, but Stanley Lieberson's A Matter of Taste: How Names, Fashions, and Culture Change may also be relevant here.)
And anyway, the great thing about ACS and OpenACS when they first arrived on the scene was that they solved web development problems better than anything else out there. That's what I care about, that they're useful tools. If I wanted to build a next-generation web development toolkit, I'd think hard about three things: What new problems I want to solve; if any other tools or techniques out there might help me solve them better; and how to carry forward all that was useful and important about my old problem-solving tools.
Now, from that rest of your post, that stuff you've already been thinking about, very good. But...
IMO, a large community is principally a side effect, not the goal.
If you want a suite of generic but popular web tools, why not just go use them? If the goal is popularity of something similar to OpenACS, well, I'd probably pick an already-popular toolkit and figure out how to both enhance it to take advantage of what I learned from OpenACS, and convince the rest of its community to adopt my changes.
If you want new and better features like those you listed above integrated into your web development toolkit, well, seems the main questions to answer are "how" and "added to which base toolkit?" In other words, enhance OpenACS to do what you want, or enhance something else to do what OpenACS does?
Those are important and interesting questions, and I'm definitely curious what answers you ultimately come up with! (Please do let us know.) But I think that so far your, "and I also want it to be popular, how do I do that?" question is poorly posed; it doesn't mesh with the rest.
Also, the Clojure folks seem to be innovative; it's not just Yet Another Implementation of Lisp on Java, they're also trying programming language ideas that are probably of some interest even if you care neither about Java nor Lisp. Yet they run on the JVM. So, you may want to talk to them, see to what degree that Java integration seems to be helping them with popularity, acceptance at large companies and other big boring institutions, etc.