Tag boosting is kinda nice, and HoT's do work. Also seems the grouped xp with a higher level is roughly halved?

I tested trying to boost a bunch of different ways. Result: frustration - they've worked pretty hard to make it not possible to power level effectively as far as I can find. Instances yeah you can mow down stuff with a higher level but the xp the lowbies get is capped out so even higher level elite give very little more than normal mobs. Tried the old WoW trick of killing stuff of the booster's level but that was still the same xp cap to the lowbies.

Rifts, same deal, not terrible but not great. Guess if you wanted to farm the factions and planarite, but it upsets the normal lowbies around. Best result I had was running quests with a high level helping finish mobs and heal once tagged - not all that much faster than doing it normal. Unfortunate that they've made it so the best xp by far is just to run the quests. I don't mind them once through but after that, meh. I've been frustrated with trying to skip collection quests and then not having ongoing quest chains as well. Has anyone had better results with trying to level without questing or only some quests?