Changelings have had at-will "transform into any humanoid shape" since 3e, and I rarely see complaints about it. If I hesitated over anything, it'd be the grab bag of innate spells that come packaged along side the shapeshifting. The 5e standard seems to be that you get something like shapeshifting or a handful of innate spells. Not both.I'd be a little wary of the irda though, the unlimited at-will shapeshift seems a bit much for me. It's not as lore-friendly, but I'd just use Firbolg stats for them, or else limit their shapeshifting to one pre-decided form per point of proficiency bonus, as a balancing factor.