In my opinion, the lava buckets change the game too much, in the late game, most of the times people don't even fight, they only place lava, there is no more skill involved. I belive that flint and steel is enough to set a player on fire and that lava buckets are not necessary. Also there is too much fire now, noone likes to be set on fire, at first you could only get fire aspect from a level 6 enchant, now you can find fire aspect swords laying around, flint and steel, lava buckets.