I wholeheartedly agree with you and I did mention in my post that “only one game mode” is a very valid concern.
However, what you are describing is not a “no incentive to win” concern, it’s a “no incentive to attack” one. I would even probably call it an “incentive to be more aggressive”. Like you said, it would stir up the matches a little bit and add variety, which is always good for a game. But it won’t completely cure camping, it’s just human nature.
However, as is the game DOES promote aggressiveness. Not even the game really but the military science.
Everything else being equal, conflict’s outcome is determined by the concentration of forces attackers and defenders have in a certain area. Attackers (again, everything else being equal) have an advantage, because Defenders have to spread out their forces across the entire front (since they don’t know where to expect the attack) and at the same time, Attackers can concentrate their forces at the exact point where they need it. It was all very nicely demonstrated by the Germans against France in 1940 and against USSR in 1941-42.
In game’s terms, on most maps, a coordinated attack will always (ok, on average :)) win over a camping team. There are lots of examples - push through the field on Malinovka, through the valley in Lakeville, through the middle on Steppes, etc. Pushes like that, if well timed and coordinated (and of course, if the execution is not fucked up), have very high probablity of winning and I’ve seen gazillion of them winning in both Random and Clan matches. That’s just numbers - 15 tanks will always kill 5, then 5 more then the remaining 5.
The problem in Random matches is, of course, with coordination. Most people don’t want to lead anything, some people don’t want to be led, some don’t read chat, some disagree with a plan, some think “yeah you push and I will snipe from behind”… There are dozens of reasons why people don’t get organized most of the time and really majority of these reasons cannot be addressed by some magic game design decision. It’s just human nature.
Even if (actually, it’s a “when”, since the devs confirmed this mode is coming) the game designates one team as an attacker and another as a defender, guess what will happen most of the time in random matches? If there are 3 directions for attack, the attacking team will split more or less evenly between all 3, even if it doesn’t make sense tactically. And the output will again be pretty much random - how defenders spread, lucky arty shots, unlucky bounces at critical times, etc.
That’s just the nature of games like this. :)