Juggernaut doesn't have a high record of being defeated, and Doomsday can't give himself any power, he just becomes immune to the same level of attack that caused his death. If you kill him with a class 5 strength punch, he's immune to class 5 strength punches, and you have to kill him another way or increase the damage.
I think Dooms should be powered down to the point where he's strong enough to whoop multiple JL members, but still be defeatable. oh yeah, and FYI people 1.Doomsday takes months, even many years to regenerate without outside help, he doesn't just re-spawn like a video game and 2. he's resistant to what killed him, not immune (and he NEVER becomes immune to pure strength attakcs). he could get beat to death by superman, and then beat to death by some stronger than supes. oh yeah, and http://www.rapsheet.co.uk/RapSheetMain/Character2.asp?UniqueId=114 he does "evolve" to beat his opponents by developing their weaknesses.
umm...I think you misinterpreted what I said. when I said non-angry hulk, I mean he wasn't in full rage. Grundy changes way too much, someone needs to make a grundy that's not the freakin opposite of the other. he shouldn't gett his aas kicked by batman one day, then beating the schit outta superman the other.