Lowering your potency/other stats is worth it if it means you don't get a 100% damage reduction on mobs you are fighting. Resolve can be used for a solid gear reset between expacs of the same levels of gear. Everyones going to have to grind gems anyway, so doing the heroics for gear isn't going to be a huge issue. Gear resets happen every expac, some replace all previous raid gear instantly, some leave some bits viable. It's been like this for years. [Exceptions being truly OP items. Avatar stoneskin boots for example].