Once you're fully leveled and into a full set of tome gear, it's rarely necessary to put a great deal of effort in for anything but EX / Savage / Ultimate content. Normal dungeons are a joke, and Hard (Normal) trials are just a matter of figuring out the dance and how to avoid the plentiful AoE attacks thrown out by bosses. I do make an effort to use cooldowns for trash packs but all said it's just not really necessary and I'd rather save them for the tankbuster move every boss seems to have these days.

... until the next expansion anyway, where players' complacency will lead to them dying as wizened tanks refuse to pull extra trash packs they rushed ahead to pick up off of them. (Speedrunning bleeding edge leveling content is not a viable tactic!)