Those gametypes have been around for a long time. Maybe instead of elite slayer it should let you be an elite in the game if you wanted to be one like in H2.
Juggernaut is basically knowing the right time when to kill him. Let everyone else do the dirty work and move in when his shields are pretty weak.
I was never a fan of slayer pro. One of the points of no radar is to promote team communication which obviously you don't need in RP. It leads to a lot of beatdowns which is annoying because you can't be looking everywhere at once all the time.
I've also been screwed out of so many perfections by stupid crap that it's not even funny, so I understand why you're mad.