Of course with some comprimise, because nobody wants to wait 2 hours in front of their computers just to see some action(I'm looking at you WW2OL). But it doesn't necessarily mean we can't get realistic simulation of infantry and vehicles together, which is FUN.
Keep the realistic gameplay(weapon handling, damage, armor and systems modelling etc) but at the same time take measures to ensure players can find decent action, and you get a pretty decent game.
The problem is this game would cost something like 50 mil, and would take 5-10 years to make :) The only way I see it could be done is to make a modular game (like DCS) and update it constantly over a long time. I'm actually curious about what that new DCS engine will deliver. Maybe we'll get armor(tank) modules over time and in time infantry all working together in a multiplayer environment. Yes it's a pipe dream, but not impossible.