I wouldn't use it, I can only imagine how much more annoying path-finding is with such unit sizes. I wouldn't mind a small increase to allow for greater variety but otherwise no.... (meaning unit size variety. There seems to be 3 infantry sizes with a couple exceptions. 120, 90 and 60 for various units, upping the max a bit could allow for some interesting unit size balancing choices)
Also, there are entire factions which are not balanced or polished in any way - it seems likely no one on the team has even loaded them up before! So I think other things should be focused on.
edit: oh this is old, oh well, i stand by my words!