I think it's because HTC would rather see everyone together. One of the reasons GVs are in the game is so that they can be bombed. Wirbles are in the game to shoot down planes, osties to shoot down buffs.
Fighter who hates getting jumped, killed, ganged all the time learn to wing up with a wing man or two. GVers can do the same. When hunting for tanks bring along a guy that likes wirbles and let him have a field day grabbing scalps of those looking to bomb some GVs.
It's ALL part of the game.
Hate to drop the bomb on your post but you fail to recognize that our world is dominated by MARKETING and the almighty dollar and not what one person or one CEO thinks. It's all about money and market share...and more importaintly--
WHAT THE CONSUMER WANTS. (Hear the alarm clock going off?)
The OP has already stated he went to another game that was all tanks and was unhappy with the quality of the game. How hard is it to understand that there is a CASH paying population out there (besides AH subscribers) willing to pay for a better game they ARE happy with. It's called consolidating market share. If there's a worldwide consumer interest in an all-gv arena with greater opportunity for gv strategy (in numbers or in small squad tactics) who enjoy gv-only arena. How does HTC win that share? By doing it better than anyone else on the internet--and it sounds like they already have (sans an all-gv arena to date). What skin is that off HTC's nose to offer an all gv arena if there's legitimate worldwide paying subscriber market share to be had? Money talks.
Air Warrior was awesome in the fact they had like 9 Relaxed realism Europe Arenas and 9 Relaxed realism Pacific Arenas, beginner arenas and then "Full realism" areans. They didn't give a chunky pile what arena someone played in or if they played "all together"...they cared about that monthy subscription payment clearing every month...and not much else. AW DIED because they were happy to turn it into a cash cow, not develop the game further (R&D--the graphics were rudamentary at best for the time) and other mis-management.
If a company refuses to give the consumer what they want the consumer will continue looking for what they want weather box game or live. Garnering another subscription paying segment of the gaming community would be another feather in HTC's cap..not a burden. Just ask Dale if another 300-400 year-in/year-out subs wouldn't be welcomed if they could play in their own sandbox.
Just as you enjoy being the Walter Mitty WWII fighter pilot, there are plenty of people out there who want the be the Patton, Rommel, Montgomery, Walter Mitty.
Just because YOU don't want it doesn't mean that THEY dont.