I think this XP globes are just too drastic. It was totally unnecessary to make such huge change, to change so many aspect of the game at once!
I think devs should start by making XP globes purely cosmetic. If it proves to be good, they could start experiment with things like XP collecting range, making globes visible etc…
Additionally, it XP globes will be problematic (and I am sure they will be more than just problematic) it will be pretty hard to say what exactly is the most broken thing.