I've only been playing for 20-30 minutes, but I'm really enjoying the new tactical battles. Having units start off close is definitely a good change.
I like the way heroes appear. I like have choice. I really really like the new skills trees.
I miss the map debris though. I know why it was removed, but I miss it.
Starting with a couple of units is a good change, helps pick up the pace early.
I usually play Peridon. I love their new ability. It costs a ton of mana, but it adds a lot of character to the race.
I like the new weapon special ability.
It seems like initial monsters lairs on default are REALLY strong. Around my city were 4 medium groups and 1 strong group. Ouch. I have mixed feeling about this. On the one hand I like that it is harder to clear lairs and you need to focus on spawned monsters at first. On the other hand... well actually I guess there really is no on the other hand. I just hope the AI can handle the new settings.
I enjoyed playing FE, I'm really super digging FE:LH. Overall, this is a major step in the right direction. Good job Stardock!
Oh, and I haven't hit any bugs yet *cross fingers*