The thing with rpgs is that the term is kind of vague. There's the Ultima games, the Ultima Underworld games and other dungeon crawlers, there's Japanese RPGs like what RPG Maker is meant to make, there's the isometric type like Planescape Torment/Fallout/Arcanum, there's the Elder Scrolls type, and there's ones like Knights of Pen and Paper 1 & 2.
AGS could work fine for battle systems for some of them, but is ill suited for something like Elder Scrolls (which should be 3d anyway). Turn based battle is the type that AGS is most suited for. I tried it a couple months ago, but ran out of time and didn't know quite enough. I'm fairly certain I could do it now if I had time, though...
Of course you didn't mention what kind of battle you tried to script. But I assume it's real time since you mention fast paced, etc.