The biggest change I would recommend is that they start making some of the premium models a bit smaller; or, in a second, smaller size (thus increasing the number of actual models). The most common question people have when discussing the higher end models is some form of "is it too big." This is a clear indicator that the size is turning off potential customers.
I know I would gladly purchase a MTG 1000 series if it were just a bit smaller (in particular, the MTG S1000BD-5A). I was really on the fence about it and decided not to. I look at my GW A1100-1A3 and can not see myself going any larger, and the specs for the MTG indicate it is another, significant size jump upward.
What I am currently wearing; as you can see, I really can't go any larger:
The official photo:
from here
What I would really like to wear, if it were just a little smaller:
from here