Judging from the art itself, it looks pretty good. Lion-O is younger, which I'm totally fine with, and maybe that just helps out more as he becomes the leader. Cheetara looks a bit too young(Maybe around Lion-O's age? Can't really tell), but would need to hear her voice first. Same thing with Panthro too. He looks different than his past self, so how his characterization and voice play out will be hit or miss for some people.
Oh, and Tygra gets a gun now along with the whip, sweet. I never really disliked the whip, but I guess out of all the ThunderCats, he was never really my favorite. Lion-O was the leader, Panthro the strong tech guy, Cheetara the fast psychic one(right? its been a while), the kids were the kids, Snarf was...Snarf, and Tygra had the whip which made him invisible (and cause fires? Again, its been a while). I guess while he was cool, he was never really as cool as the rest of them(though obviously above Snarf, though that should go without saying. =P).
In the end, I hope it does well. A bit too soon to say "MY CHILDHOOD IS FOREVER RUINED!!!!", but at the very least, it could be worse! Though I'm liking the art alot so far, and I guess it depends how the battles are(story wise they don't have to change up too much but you never know).