Season 2 is good to great, not mediocre. It’s just that S3 and S4 are even better. Season 1 you can skip most of the fillers if you’re in a hurry. There’s a plenty of curated S1 episode lists on the internet that tell you which episodes you don’t want to miss. It’s much better this way than the usual "first season excellent, second season okay, the rest are crud and only exist to make money".

There are several stand-out episodes in season 1 and 2, as well as several stand-out scenes; plus the second half of season 2 is not mediocre. You also miss out on character and world-building that happens in those episodes that help contextualize a lot of the later seasons.

Plus, many reactors now have liked season 1 a lot better than when it initially aired.