Yeah barrels deals good damage via throw. It is also often a good idea to use sneak and oneshot bosses by placing 2-3 barrels next to them. Like 1x Poison and 2x Gas is like 1500 damage opener.
I don't think Glas Cannon is as good as you state. I have 11 or 12 speed and in total I have 12 aps per round without GC. Obviously I could bring that to around 22 with GC, but that wouldn't benefit me that much. It doesn't matter how often I can strike as long as I end my turn on stealth, however it matters if I get poison or burning, because that breaks it.
If I want to do an action that involves more AP all I need to do is wait a turn, but the mobs simply cannot withstand that raw power of a rogue to begin with.
