I have tried a few launchers on my E4GT, even paid for one, but in the end I went back to TW. I don't know, it just feels more "put together right" using TW over the launchers. Something irks me when I turn the phone on and all of a sudden all my shortcuts to apps and folders went bye bye after a reboot. Either way, I wish they would have changed some of the core apps and made them prettier, like the messaging app...nothing changed there, it looks exactly the same. The icons for mail, phone, messaging all look the same as well, slightly disappointing there.
I don't think they will let you switch to the stock ICS launcher. I know it works on the leaked ICS roms for the E4GT but who knows if they will keep that in the final build.
I also like the new lockscreen. Too bad noone bothered making a video about whether the bottom 4 apps can be changed and what it looks like when you want to jump directly into those apps from the lockscreen. Do you swipe the icon upwards or how does that work?