I don't know if the M-18 will ever be added. If it is it will need to be massively perked. AH's much less cluttered than reality, allow full road speed off road, terrain would be much too favorable to the M-18.
My personal preference is that it is never added.
some of these maps the M-18 would die before any chance of being able to utilize the terrain. These needed speed and cover to get kills. some of these maps are so open that they would be seen far away like the M8 and would be neutralized quickly. Also, some tank battles have NO room to maneuver the M-18. I use the M8 alot and it is a terrain reliant unit. The M-18 would have the exact same problem and would be as usable as the new M4 76mm except with an aircraft problem instead of a ground problem. (btw, the M-18 only had 35mm armor MAXIMUM. a 20mm could kill it theoretically just like it can kill M8s and M3s...
I'm not a tank expert. I'm hardly even a tank enthusiast. My only experience with tracks comes from playing around on a tracked bobcat skid-steer. Even if a tracked vehicle could not pivot in place (true zero turn) by means of running one track forward and the other in reverse, it could/should still be able to lock one track up and move forward/reverse the other track giving the next best thing to zero turn. Im not a "coader", but once a system of driving a tank like it has 2 tracks instead of 4 wheels has been implemented, if a tank did not have zero turn capability (Pzr Mk IV?) then Im sure it could be modeled properly.
The way the tracked vehicles are modeled now lend them to having 4 wheels. That limits mobility in all directions vs if the tanks actually had tracks.
Also.. stop and think what tanks would be like in AH if there could be a driver AND a gunner inside one vehicle just like the aircraft with gunner.
yes, almost all tracked vehicles of WWII had no zero turn (excluding the TigerI "PnzrVI", Panther "PnzrV", TigerII, and i believe very late PnzrIVs and T34/85s). Allied tanks excluding the 34/85 did not implement zero turn until the M26 IIRC.
+1 to the idea of coading brake turning in the tanks track system to allow near zero turn and +1 to Tiger zero turn.
Aces High already allows a tank gunner although many choose not to do this due to the fact they trust themselves more than a gunner or it is too hard to teamwork with a tank gunner. I've successfully gunned PnzrIVs for people for fun though and it is something that i recommend for a more fun experience if you dont care about "winning" or score horing...