I'm not sure if this has been mentioned, or brought up recently.
But what about doing a larger fix to the system in general to even everything out.
by the time you hit level 20, hell even maybe 15, everything is 100% hit able all the time on a non gimped character. Because of this, we see mobs with blanket immunities and HP values rivaling Apple's Stock value.
Rather then decreasing combat speed, why not increase Monsters AC while Reducing HP. Make it so "standard" (used loosely, not looking at someone in full Raid/Epic/Greensteel) gear would be hitting trash 90~100% of the time, Red name bosses 80~90% of the time. and Purple raid bosses 70~80% of the time. If the scales are re-balanced properly I would think that because mobs are receiving less blows the system wouldn't lag to the swarm of numbers flying at it, while at the same time combat takes just as long (due to reduced HP values), and combat speed remains the same keeping people happy.
Granted, since THF get less attacks per min, maybe throw them a bone and leave them with double strike, or extra str bonus or something. So that when they hit they hit HARD where was the TWF people are just the flurry of smaller blows. And S&B.... Alot more has to be reworked for S&B to work in combat