Well this is clearly a borderline case: what is just too cramped to some is just feasible to others.
Comparing button distances with those of any 4-button controller does not make much sense, you have to compare with existing 6-button controllers if you want to make such an argument. As an analogy: a dpad can be quite compact and still work, but if it were to have 6 directions (say, some kind of 3D dpad) instead of 4, things would be very different.
The lengths ED and Askarus went through to test this idea show to me that they take it very seriously, and if they judge that it does not work well enough, then I'll take their word for it. I don't think a poll would be very useful: most of the people would vote based on how it looks, not on how it feels. The opinion of those who tried both options are much more relevant.
Looking at the difference between Askarus' mod and GG's proposal, I don't think the precision of the mod was insufficient to get a good idea of how it would feel. You can of course keep requesting more precise executions, but there's no end to that kind of argument. I can imagine extending this thread with a dozen pages of the type "ok, it's more precise now and still doesn't work, but there's still half a mm difference!" ... "ok, it's exact now and still doesn't work, but you should use the real buttons, not ones from a DS" ... "ok, but this is just a hardware hack, in a mass-produced unit it will work better!"