"Roguish" Druid is a great concept, but I would suggest that you may find Land Druid more appealing. Moon Druid turns Wild Shape from a utility tool into a weapon, but as a burglar you don't really need that "big gun" that Circle of the Moon offers. Land Druid, on the other hand both enhances your spellcasting with an expanded spell list and offers more utility features that complement a roguish approach to scenarios (e.g. Lands Stride). The Underdark spells, in particular, are pretty good for a burglar sort.