There's something that I've always found mildly annoying in many tab-target MMOs, and in this case its the seemingly arbitrary bonuses that mobs and characters get to their defense and resistances based purely on their assigned level.

I understand the intent behind this type of mechanic is to keep players operating within their relevant power bracket, even if they've managed to pull of some absurd solo-grinding build to take advantage of the XP bonus for taking on more powerful monsters. I disagree that this is a desirable outcome.

CoH originally did not include this mechanic until people in the forums complained about power-leveling by exploiting the behaviors of certain mob groups, like Freakshow's prefference for lethal, smashing, and energy damage, to make functionally unkillable builds, even vs mobs 4 or 5 above their level. IIRC, these changes came along with the infamous ED changes.

Maybe I'm the odd one out, but I personally don't see the problem with people being able to take on powerful enemies if their build is capable. If anything, it may indicate screwyness with the powerset balance.

However, if the devs think that this is indeed a problem that needs to be addressed, I propose that rather than nerfing players abilities based on numerical level difference, eliminate the bonus for larger mobs beyond +1/2 level difference.

This way, mechanics of the character aren't altered while still discouraging people from trying to use +4/5s for grinding levels.