You can see his designs for Krang/Beebop/Rocksteady/Casey Jones/Donatello/Mikey/Raph&Shredder on his website.
Beebop
Rocksteady
Krang
Mikey
Donatello
Raph/Shredder
Casey Jones
April 
Can't say I like his designs too much but I also don't hate them, i kinda did at first but they already grew on me a bit.
Its obvious those are NOT the designs for the new cartoon but if you look through his blog THAT is pretty much his style is so expect the new cartoon to look similar like those examples above. Those designs do look like they'd work for CG.
You can tell he is a big fan of the turtles from his past posts from previous years, went all the way to the first blog post...And wow this news is from July 31st how is it that took so long to get out? Internet detectives are disappointing us