If my character wanna suicide, he has better way than suicide immolation.Erm... Well the whole point was that it's far from suicide. And even if it was (which it isn't): There are also few abilities that deal a substantial amount of AoE dmg while committing suicide - so which way would be the better way for you?
Few people complain about Berserker's self damage at PL 7 - although it's very high at that point. And he doesn't even have a powerful healing ability to counter that like the paladin has.
Because nobody tells them. It's obscured. But they see 43 raw damage per tick on SA and go all "wooot? Nooo way!".
Maybe you can quote one ability that does same amount of damage to self as suicide immolation? With high might and sworn enemy(which is bugged it applies on SA) you will do around 50 raw damage per tick to yourself. Yeah you can try heal your hp up, but I just wanna ask, does it worth doing so? The point of combat is reduce enemy hp to 0 while keep alive, and this ability which doesn't do a lot damage, counter the point of keep character alive.