Definitively download size should not be the problem. I remember downloading 70Mb patches with a 56k modem as surelly most of us have done.
Now imagine, two more months til 1.10 and then 80Mb patch available, are we really going to consider that a problem? IMO, not at all. Obviously, if we have a 100Mb patch every week, then I agree, that would be a problem.
About FPS, what AH really lacks is a flexible system to configure the detail level, and this mandatory option is available in any other sim as far as I know. Changing screen mode doesnt help at all when the problem is derived from the number of polygons. In the other hand, ground battles are not so dependant on FPS as air combat, so, a more detailed terrain for groun units wont hurt the playability.