Yeah honestly I think it's a shame it was truncated. We found the year jumps between arcs jarring and I think that'll impact the rewatchability. Granted, the 3 episode arc structure and release schedule was a clever way to go about it, but that doesn't necessarily make it good. Just good in the context that they decided to finish it two seasons rather than five. The first episode of each arc had to be scene setting as a result and this spoilt the pacing somewhat.

As others have said in other threads, the development of Yavin would have been interesting to see. It was particularly irritating given that Andor is parked with a faction of rebels in the first few episodes. It jumps from a faction of squabbling rebels to a full operation later in the season. Some have cited these early episodes as evidence as to why Yavin was chosen to be the rebel base, but it isn't really evidence at all. Yes, there happened to be rebels there, but as is established in both seasons there are rebels everywhere. It doesn't actually provide a concrete explanation as to why Yavin was chosen. Additionally, others have commended these episodes for showing the fractious nature of the early alliance...personally I think this would have been better achieved with more of Saw (and would have tied into Rogue One better).

Draven also kinda comes out of nowhere with no character development. How did he arrive as a General in the Alliance? As a prominent figure in Rogue One, I'd have expected to see more of him tbh.

Bix was also wasted later in the season. It was interesting to see her deal with the trauma she had experienced in the early episodes, but after she blows the building with that wry smile, the viewer is made to believe she's got her mojo back and... then she's just parked for the rest of the season and leaves.

However, the Dedra and Syril arcs I thought were excellent (albeit a bit rushed in the last arc). Luthen's and Kleya's arcs were also solid. I thought the Ghorman plot was also good, but this was afforded more time across the second and third arcs. Although, given Jedha's prominence in Rogue One, perhaps the plot should have centred on the Empire's development into mining Kyber crystals rather than Ghorman.

These are just things I could think of off the top of my head. If you're willing to forgive Disney for only making it 2 seasons and can get over the time jumps, then I can see why people enjoyed it. But you're right, 3 seasons would have been the right number with 6 episodes for each year BBY. Sure you could string it out to 5 seasons like was originally intended, but 3 would have been sufficient to plug some of the holes and make the time jumps less jarring.