But you are adding these on top of the already full spell progression that sorcerers get. Wizards have to give up their regular spells slots while sorcerers do not.
You can only switch saving throws once per long rest. Without meta gaming, you have to know what the enemy is resistant to and then switch. Beyond that, it's not a big deal.
I think it's fine the way it is. I think this is a general wizard that should be able to change things up a little bit. Just about every other class was given a lot of extra options for players to use while wizards only got one really good extra option.