My basis for that was my own memory and watching osso-statusbar-cpu. The CPU went to 100% when I opened it, but that happens with every application. However, with the new version, GC Dialer seemed to take longer to startup than before. I realize this is a very unscientific test, and I'm just going off my own judgement, which is why I say that it "seems" to take more CPU.

As for Python-Launcher (which I believe is what you're referring to...), from what I understand it replaces the python launcher with itself, and then makes the import gtk line REALLY quick, because it's already preloaded. So, the only thing needed for Python-Launcher compatibilty is to use python and to import gtk. If I'm wrong on any of that, please someone correct me...

[edit]Ah, it turns out that python-launcher support in GC Dialer was broken somewhere. The python binary is changed to call python-launcher, but in my gc_dialer.py, the first line is:
Change that to:
And python-launcher support will be back in. Besides, packages should take care of requiring certain versions.