I attended a PHP conference a couple of years ago, where Rasmus Lerdorf (the guy who created PHP originally) decried all frameworks as explicative (and this conference had CakeDC, a major Cake PHP dev house, as a sponsor). While I don't fully agree with the sentiment (frameworks aren't completely worthless), you also have to understand that you're adding an intermediate layer to your codebase having one. Sometimes it simplifies things, sometimes it makes them more complex.
Zend Framework 1, for instance, was notoriously slow (a fact even the guy at Zend, who wrote most of it, agreed with). Magento built their early platform on this and it dragged horribly. I was also unimpressed with how well ZF code flowed. While it did MVC well, it was like having to relearn how to code (and I had been doing PHP for over 3 years at this point). I understood why they were doing things that way but they abstracted everything to the point where I couldn't keep track of my program flow anymore (it's bad when your stack trace, the list of everything that lead up to an error, is 50 lines long). I have not tried ZF2 but I have heard it is significantly faster (it uses namespaces and auto-includes instead of a million default includes). Still, I don't think it's easier or better.
What we do is we write our own backend and use Smarty for the frontend. It takes a little longer up front but it's written using standard objects and we have much better control. The key to our simplicity is copious documentation (inside and outside the code). Someone coming into our company would only need to know PHP to work in it, as opposed to knowing PHP + something else. Remember, someone will have to maintain this stuff for you and you don't want to pigeon-hole yourself into some framework few people know.
As an aside, they were selling T-Shirts at this conference that said "Life is too short for Java." I do agree 100% with that statement. It's a good move to ditch Java for PHP.