I don't buy many 5e products but most of the cover art, including Tasha's, I find really tepid. Of course, it's incredibly well done, but it doesn't excite me at all.
One exception would be the Ghosts of Saltmarsh cover, which I'm pretty fond of.
I noticed when I was flipping through the Art and Arcana book, the later art just seems to lack any charm to me. The early stuff is really goofy, but very endearing. The mid period is much better and I generally like. The latter stuff is very proficient, but it just seems boring to me. I'm not sure why exactly.