Nope! As long as there’s only one copy of it in your deck and it matches the color identity, you’re fine. There’s actually even a handful of planeswalkers (2015 or 2014 commander precons I think) that can be your commander.
They do follow the legendary rule, where you can’t have more than one with the same name. It used to be wider, where you couldn’t have like Jace the Mind Sculptor out with Jace Beleren, but they recently modified that as well. Doesn’t limit you from putting up to 4 in the deck, but you’d usually stick to 2-3 in normal formats because you don’t want to have that dead card in your hand.
This is absolutely the most PW’s I’ve run in a deck however, and if she was cheaper, I’d run Vess, but I don’t feel like shelling out 25 bucks on the off chance of her ult going off. Instead I stick with those three. Dack Steals artifacts, Saheeli sells shoddy copies from her basement, and Ashiok’s got a shovel on his back for the deep digging. All three are pretty useful at any point in the game.
You could add more Hualti’s to the deck if you wanted to, even the other versions of her. You just can’t have the same version out twice at the same time.