The reason being was because he was so good it overshadowed other easy to get, yet acceptable ninjas that f2p have access to. Kisame is fine and hidan is actually pretty solid (even though his new form is overshadowing him, but that's new even for the p2w crowd). Deidara was also recently added and from some rumors I heard itachi becomes fairly solid later (plus, he has a bit of that "annoyance factor" that tobi has).

Tobi really had way too much going for him. The revive gave him a 40% health boost, a cc clear/debuff removal and could break a combo chain for a round if it was inititated on him with low health. His mystery I had less issues with, but 20 chakra for solid initial damage, immolating, and being able to follow that with a chase that damages even more than the mystery itself was a bit much. The chase was huge, maybe if it was created by something less common like repulse I would be ok with it - but tons of good ninjas cause knockdown.

I understand it *s because it feels like f2p is nerfed by this, and to an extent it is. But it's because he was/is just such an amazing utility tool that it outshined other, completely acceptable ninjas. Why do you think he was used so much? Because even amongst p2w people he could still overshadow many other options.