Unlike grand company seals and tomestone you can't farm EXP on 1 class to give it to another. So if you want 6to level a tank you must play as a tank and more EXP mean less time spent in queue for leveling purpose since you won't need that EXP once you hit lvl cap.

And even if you don't have the @tank@ EXP bonus, daily roulette remain a good way to farm EXP so I really doubt that many player do the daily roulette while leveling because they got that tank EXP bonus while I'm sure that many level a tank as alt and don't play him as much once they hit lvl cap.

Whats your tought ?