Engines, plugins, migrations.. and moaning

Hi,

If I'm not mistaken, placing controllers, views and especially migrations in plain plugins doesn't work. It seems the only way to do this is with engines..

Third party applications, with third party repositories, cry out to be kept separate from the main app. Once you merge foreign code with your own keeping up on fixes can be an unnecessary nightmare. (A classic app in this category is forum software where integration is barely more than translating user models.)

So.. why do people moan about engines? Is there some magical solution/solutions out there we should be using as a replacement? And if not, can anyone invisage the future?.. I can't see engines style functionality getting into the core but I can't see engines going away for a while.. ?

cheers -henry