yes but as the other side I do something like this (Same number of Inf, Tanks):
6 inf, 3 T : 1 inf : 3 T
1 inf : 1 inf : 5 inf
1 inf : 1 inf : 5 inf
6 inf, 3 T : 1 inf : 3 T
I could attack your two outer territories with my ‘stacks’ of 6 inf, 3 T and then you can only counter attack with 6 inf, 3 T each, with myself on defense. So you don’t attack my stacks because I likely win that. This will force you to retreat or stack the territory between my ‘stacks’ and your capital.
I agree, the size of the map will diminish the use of ‘mega-stacks’, but there will still be 2-3 stacks per side on the eastern front.