I like the new armor system. The first game had an excellent engine and well-designed encounters that were ultimately for naught, since the game gave you so many resources to deal with them that it ended up being rather easy. That issue was my main complaint with the first game and it seems to have been addressed(somewhat haphazardly to be sure) by the armor system.
I too would like a more detailed system of defenses, but the fact is the current one gets the job done in slowing down the pace of combat and making it more deliberate. Now you can't get away with alpha strikes and CC spam and other factors become more important than they used to be, like positioning and buffs. This makes the game more challenging, more varied and overall a better employment of the excellent engine.
People who do not like longer encounters need to remember that due to Larian's philosophy of no respawns and no random encounters, there are precious few fights in this game compared to most RPGs with a heavy combat component. There have been few, if any, encounters that I would describe as "trash mobs" so far in my run. Hence making the encounters more difficult, more deliberate, and indeed, longer, can only work to their advantage.
To be sure this was achieved, as some pointed out, by somewhat gutting the character system and the old system of defenses. But I think it was a fair trade-off for more tactical combat. Said combat was always this franchise's main selling point, and Larian was wise to build on its strengths.
To be fair, I have yet to see how well midgame and late game hold up to the level of the early game. I suspect better equipment, especially through crafting, will hasten the pace of combat greatly and make it easier as well. Already at level 5 I think the sharpest spike is well behind me due to the quality loot and skills that I have accumulated, but the game still requires me to think my tactics through and is still fun.
Apart from that, the overworld exploration was much improved as well, plenty of secret areas, shortcuts and loot. Not much in the way of resource management once you get the healing spell (and poison to hit Fane with) though. Also, I liked that there is not as much dialogue as in the first game, and that what dialogue there is is of better quality and much reduced derp. Overall seems like an improvement.