This is a question that has come up in the Divinity: OS thread because Volly said most Bioware games have better combat, and I said no, none has. Especially since a Bioware game is the RPG with the worst combat ever: NWN. Some people disagreed and claimed Arcanum was worse (lol no). But Arcanum was passable. It's always bashed for its combat, but it's not the combat system that sucks hard, it's the encounter design for the most part.
Apart from some horrible shovelware Diablo clones whose names I already forgot, which had Diablo combat that felt clunky and un-fluent, NWN has the worst combat in any RPG I played. It's the worst form of RTwP - you can do solid RTwP, but NWN does everything wrong that can be done wrong with such a system. It is slow as fuck, when you play a fighter you spend more time watching two dudes whack each other with long pauses between each strike than actually issuing commands to your character. A single combat turn takes quite long to actually play out, it's much slower than in, say, Baldur's Gate, a game with solid RTwP combat. This could be excused if you actually had things to do during these turns, like commanding a party. But oh, snap! NWN only allows for the control of a single character. Party members cannot be controlled, nope. It's basically single character D&D, and dungeon crawling with only one character in D&D is fucking pointless. Multiplayer can be fun, yes, but the singleplayer has boring as fuck combat because of this. Most fights, especially trash mob encounters, just horribly drag on and have little excitement to them. The only classes that may actually be fun are those with spells because they have more to do than just click an enemy and wait for all the long fighting animations to play out. But playing a wizard in D&D without backup is certain death at low level, and taking a fighter companion along means your tank behaves like an idiot and might run into too difficult situations for him, and you have no control over this because you cannot command henchmen (apart from general commands like "stay close to me!").
There are some worthwile modules for NWN, but the best of them excel because of their non-combat parts. The combat in NWN is unredeemably bad.
If you disagree, show me one game with worse combat (there probably are some Russian shovelware games that are worse).