I noted this as well when I upgraded my blog to Rails 3 during the bugmash last month.   Rails suddenly has a lot more moving parts, and understanding the internals is much more difficult than it used to be.  However as a Rails developer for almost 5 years (gosh has it been that long?) every single change adds an order of magnitude more flexibility than complexity.  The surface API has grown remarkably little, but the modularity and internal API stability is dramatically improved.<p>The days of Rails being the scrappy upstart are over, but I think the culture and capabilities of Ruby have largely prevented the nightmarish type of scenarios that J2EE developed a reputation for.  I guess it's only fair to give it another 5-10 years and see what it looks like, but developing with Rails feels just as agile as ever even if the learning curve has been steepened.