I just saw a promo for it, and I have to agree, up until I saw the main characters, I felt like I was watching the trailer of some off-brand CGI movie from the early 2000s, that totally took me by surprise.
Then again, the Ice Age franchise has been an interesting condundrum, if you ask me. The overall animation has improved over the sequels, yes, but, I would argue that the character designs have declined since the first movie; just take a look at these glyptodons from the first movie compared to how they looked in the sequels.