As per title, the thought occured to me:
What if during level synched content (mainly dungeons) only your stats got reduced but you kept your abilities ?
One of the main complaint I see and share about roulettes and running dungeons is that the vast majority of it is played at levels where most job do not have access to most of their skillset.
While I understand this during the levelling/story portion as you progress and learn your job, once those abilities are obtained it is kind of annoying to spend so much time restrained from using them for a lot of the available content.
Most of the dungeon content is not difficult to begin with, I don't think it'd change things that much, but will make playing the jobs there more satisfying.
Plus, it lets new players see a glimpse of their future full kits when pairing up with synched players.
Though I do understand that it might be a bit much sometimes, so maybe synching the abilities to (for example) 10 levels above the dungeon's cap to a minimum of 50 or 60? (just so synching to level 50 and less) doesn't feel as bad as it does now.
Alright that's about it, just a passing idea I had while discussing with someone about partywide damage buffs and other mechanics.