there are many parts of Cyanogen that i miss and make stock ROMs modified or not lacking. there are so many menus that are locked and non-visible in stock ROMs, and apps needed to pull off a good portion of CM7's tricks--which take up space and RAM, and are not nearly as good. for example, i cannot force my phone to ignore 3G and stay in 2G data mode. i can kill data, or use wifi, or use 3G which autoselects between it and 2G if weak--which eats battery. in addition, it takes an app to disable the lock screen or add/remove elements, which eats up valuable (and limited on the Merit/Avail) internal storage. there are also things that REQUIRE the specific scripts of CyanogenMod to work. 2G menu being one of 'em.
"If you treat your system like a kiln, don't be surprised when a brick comes out the other side."