I haven't played any multiplayer due to my bad internet. I will say, though, that from what I've seen from videos, it certainly looks a lot better than singleplayer when it comes to combat. My criticisms are completely for single-player, just so you know.
Let's take a look at the sieges. They're a great spectacle at first, but after dozens of hours in Warband, you can easily see the problems:
- In literally every siege, both armies just rush to the chokepoint and stay there until one side runs out of troops. This is probably the worst thing about them, to be honest.
- There are no tactics in siege-mode. Attackers keep their archers back and make everyone else charge. Defenders don't even have to do that since the AI does everything for them anyways. Charging the troops as the defender just screws up the placement anyways.
- When attacking, the best tactic for the player himself/herself to do is to jump behind the enemy mob, and then just spam the attack button. You can spend a good while doing this before either the archers or melee troops finally decide to do something about you, and even then, it's only a handful of them that do at that point.
- Despite how it would be realistically, siege towers are worse than ladders in M&B. Your troops don't board it until it finally reaches the wall. Until then, your army will spend several minutes out in the open. If you have any troops without shields, then they will be annihilated by arrows. It doesn't help that you can't choose between the two and it actually just depends on the castle/city.
- With the way reinforcements work in the game, battles can take ages. Since the game can't handle hundreds of troops in the same instance, it makes them come out in waves (I believe the max for vanilla is 150 troops, for both sides combined). Because of this, you have to wait for each wave of troops to die off. If all the troops in both armies spawned into the map (or even half) at once, the sieges would all be over in mere minutes. This is a technological limitation rather than a choice, I know, but it's still worth pointing out.
...and that's just the sieges. My complaints are probably pointless, since they seem to fixing a lot of these problems in Bannerlord... but whatever.
