Given what you've described I'd suggest you take just one more friendly unbiased look at Rails 3... and if after that it's still not your cup of tea then fair is fair. Maybe you won't choose to develop with it, but maybe you also won't choose bash it. It's pretty cool and I believe it was an attempt by Rails developers to address your very concerns. Most major components can now be easily swapped via Railties thanks to the decoupling efforts.
Don't get me wrong. I really like Ruby, but I think Rails has become too all encompassing in places.
The architecture, like railties look pretty cool, but policy of constantly embrace and extend just leads to bloat that gets in the way when you're doing something more exotic than straight server-side CRUD.
Given what you've described I'd suggest you take just one more friendly unbiased look at Rails 3... and if after that it's still not your cup of tea then fair is fair. Maybe you won't choose to develop with it, but maybe you also won't choose bash it. It's pretty cool and I believe it was an attempt by Rails developers to address your very concerns. Most major components can now be easily swapped via Railties thanks to the decoupling efforts.
http://edgeapi.rubyonrails.org/classes/Rails/Railtie.html