it makes no sense to not have a combined arms mode. no sense at all. also you shouldnt be so worried about the balance, i've played a lot of sims with combined arms and trust me that it's not exactly easy to spot a tank sitting under a tree from the air :). obviously you won't have those gps markers on player tanks.
Maybe you are right, there are differnt ways to make it work, Im just worry how it will play out with tanks when planes can take out most of them without big problem and as tank you dont rly have any way to defend yourself - thats biggest concern for me .
Ships can ofc survive longer and most of them have AA to defend them against planes.
One way or another, we can hope for something epic if battle will be mixed with planes tanks and ships :)
"The world breaks everyone and afterward many are strong in the broken places. But those that will not break it kills. It kills the very good and the very gentle and the very brave impartially. If you are none of these you can be sure it will kill you too but there will be no special hurry" Ernest Hemingway, A Farewell to Arms, 1929