Warband has a better combat system than Dark Souls, so...
Attacking is slow, and the animations and the way your character runs around all the time makes no attacks feel like they have any weight behind them. There is also very little variation in attacks, from what I can tell, there are three types of strikes: horizontal slash, vertical slash, and poke. Some weapons modify the pattern by removing certain attacks. There are no combos as far as I can tell, and the lack of a stamina system, the slow movement speed, and no dodges make the duels pretty boring slashfests, even when watching battles on youtube with very enthusiastic commentators.
You should try it before claiming it's boring. Once you start getting some decent gear and your character is skilled enough, battles become pretty fun.
The attack speed isn't as slow as you're making it out to be, it's sligthly slower than DS (unless your talking about DS3).
There's only 2 types of attack in DS and there's no combos. Plus Warband as more skill base mechanics to compensate, such as chambering.
The weapons in Warband are tied to alot of stats and are influenced by quite a few factors - wich make your choice of weapons and how you attack an important matter.
Not having a stamina system does not make a game's melee combat bad. Like all mechanics in a game it must be carfully though out if it's necessary or not and if it's implementation would enchance the gameplay. And in Warband's case it probably wouldn't since you are expected to partake in large scale battles.
Alas if you don't seem keen on giving it chance than try one of these 3 games: Dark Messiah, Nioh, Severance: Blade of Darkness.
These I garantee you have better combat than any FromSoft game.