Are there any monks in your party? If so, the answer is a resounding no. Monks are extremely reliant on stun (too much so IMO, but it's how the class is built). Stunning the boss is the monk's opportunity to shine. The rest of the time, they're just mediocre warriors.Would it be reasonable to say that all/most undead and constructs have immunity to stun as a house rule?
If there are no monks, it's probably fine. But in that case I doubt you'd be asking.
PCs have precisely zero non-magical ways to stun things*, so it certainly wouldn't cause any problems. It also wouldn't do anything.Maybe they could be immune to "mundane" stuns but remember that even the monks stunning fist comes from his use and manipulation of chi and that one more level and his unarmed strikes count as magical.
*If you consider Stunning Strike magical, I assume you feel the same way about the soulknife's Rend Mind.