Micro transactions can be good and bad. Segd seems confused.
RIOT games, who make League of Legends will take your money for a thousand things, but they are all cosmetic changes, you cannot buy the ability to win.
But World of Tanks IS a pay to win game. You cannot get the effective ammo without real money, and the best way to get an effective tank is a/ grind for months or b/ make a single instant payment: This is Pay to win.
lolwat.
BS, WoT is very much not pay2win.
You cannot advance to higher tiers by paying for it, everyone has to grind their way through (although you can get there slightly faster with a premium account). Also, every tank is effective... in it's own tier.
Premium shells - lol. They are there, if you are awful and wish to splash tons of cash per shell to slightly improve your performance. They do not do more damage, they only have slightly better penetration rating. You will penetrate the same tanks with regular shells, if you hit their weak spots. Also, they can now be bought for regular credits (still expensive).
Basically, what you spend cash in that game for, is cosmetic stuff, a few special tanks (which are by no means better than the normal tanks) and a slightly faster progression.