I'm not sure what you want in the way of unified startbutton API. Even within KDE itself it has Lancelot, Kickoff, and Homerun, all providing a sliding scale of classical start menu to Unity / Gnome / Windows 8 style dash. That is one domain that has demonstrably not one ultimate answer, and I'm a big fan of the KDE attitude of making multiple choices available with the default being moderate (search by default, tabs for programs / recents / power / etc).
I tried getting used to the new Ubuntu way of doing things, which I've heard is based on the Apple way of doing things. I didn't care for it.
Edit: I also run some gsettings commands to turn menu icons back on. Also, you can return menus to the owning application in the Unity UI, right-click the Desktop, Change Desktop Background, select Behavior tab and it's there.
I agree in basically every other context that it is annoying/useless, but for smallish laptop screens it's still not bad.