The main thing is, RTW battle speed isn't that exagerating.... for the numbers of men it suggest is on the field. in RTW you could have most around 3000 men in a fight while most involve usually about 1-2k... that would be a very small battle in most historical time periods.

obviously, fighting with 10x the men will take a whole lot longer than a battle involving much less number (everything else staying the same). most of the major battles in roman times both sides will have well over 10k men, that's 10x more than what we could achieve in the game, and usually the extra number is not simply a x10 factor, but usually much longer.

Another thing on battle was that usually in larger confrontations neither side will move in very fast unless they are positve (or precieve positive) of their superior strength. for example Ceaser vs Pompey, both side faced off on the field trying to lure each other to attack for days before they finally engaged, the battle itself didn't last all that long as Pompey's cav charge got demolished by a surpise hidden wing of ceaser.

Let's face it, fighting on walls or in cities in RTW (if both sides are relatively close) takes forever, that's kinda realistic, but most ppl don't like it much either.