Season 1 and 2 have some good episodes here and there, especially season 2. And although I think the later seasons were much better, I liked how in seasons 1-2 they stuck to the 'One ship alone exploring deep space' theme of the original.
The problem with season 1 was they basically had really stupid premises, they were overly committed to making Wesley the wonderkid, and they had a really one dimensional approach to characterization in general, making all the aliens seem like idiots and most of the cast seem ancillary.
(And the set designers liked dry ice way too much).
They were basically still trying to be TOS only had no idea what worked about TOS.