That's pretty unreasonably inconvenient, cumbersome, and centralized for common users looking for minor changes, on top of not being geared toward allowing optional targeted improvements only some users may want/need, but to improve the standard code for everyone. - Not that to say it's bad in any way, just not geared toward what I'm thinking of.
Trust is an issue, but this is probably one of the most reputation-emphasizing communities on Earth. I mean - the devs didn't originally say "No, you can't release new Bitcoin clients, because they may contain malicious code" but AFAIK, there isn't a rampant problem of malicious clients out in the wild. People pop up fairly frequently with malicious software to steal Bitcoins, but it isn't the result of Bitcoin mods. It would create new avenues to distribute it, but for scammers, there are already viable ways to log keys from people willing to download and run software (sometimes even without consent to run it!).
It just seems weird to me, that there's this revolutionary community-driven open-source product, and nobody can change it without recompiling it, leaving it to the democracy/dictatorship/whatever of Github. So, we get Client A, Client B, Client C, Client D, and Client E. Take your pick, but what you get is almost certainly all you'll get unless the developers either themselves implement or approve implementation of a change. Plugins are superior for end-users looking for alternatives to every decision made for QT, functionally, because they aren't necessarily broken each time the core software is updated. With code changes, you have to recompile every single time.
This isn't really something I should be throwing at Bitcoin-QT devs, either, because AFAIK, there are no easily-modified Bitcoin clients. Mostly just a curiosity devils'-advocate question I don't expect people to waste their time answering should they think it ridiculously far-fetched -- thanks for the responses.
(I don't know what I'm talking about! [bump])