I think if the new game+ main scenario (at least) quests gave some experience points it will be more played.

Of course if it give too much then people will only do that, but if you limit to experience points once per major patch, it will mean it will reset 6 times per expansion and soon with 6.0 we will have 18 class to level up. (BLU does not get exp)

It does nt need to be alot just a little, because the 50/60/70 quests will also have a little and people will do the dungeons / fates / roulettes .... so just a little and maybe only up to level 70 (last before expansion cap) if you re afraid for the last expansion.

A little push but not too push that will make people take time doing new game+ i think and it could be great.