Though I don't think the trailer looks any good, most of the complaining about stuff is the usual 'who can be the funniest person on the internet' style childish boy humour bull**** that usually accompanies these sorts of films..
As someone who LOATHED the stage version, the only thing that was even remotely iconic and memorable about it for me (apart from a few songs) was the choreography and the way the cats moved.
In fairness to Hooper, who is always unfairly judged on this board, what he has done is really the only way he could've gone to commit the only enjoyable aspect of the show to film.
While it is true the best way to do it would've either been with traditional hand drawn animation or CGI cats as far as the story, music and visuals go, there is no way to do it in either of those formats and retain the iconic choreography, just like there is no way to make photo realistic animals emote like humans in The Lion King. Fully CGI'd or animated cats in their original scales doing that choreography would've looked 100 times more ridiculous than this does.
Everyone is whinging about the CGI in the trailer, but trailers never have finished CGI in them. They have literally edited the trailer with raw footage and quickly CGI'd those shots to get something out. The completed version I'm sure will look very different, especially after all the criticism.
The cats in the stage version also wore fur coats so that criticism is just stupid.
Lastly, just like Avatar and the like that have weird looking CGI creations in them, the cats may look weird at first in a 2 minute trailer, but you will soon get used to their appearance in their world if you're watching a whole 2 hour film.