The game was very generous with XP for its first week or so, but now that that's been nerfed we're back to a pretty slow grind. I think that's mostly okay---after all, you don't want to level up too quickly. Part of the fun is playing the game and slowly seeing your level go up, unlocking various items along the way.
I do think that the lack of maps, however, makes this feel more grindy than it should. Something is missing, and it's either the XP trickling out too slowly or there's just not enough content to unlock along the way to keep you feeling like you've achieved something each session.