In practise, end-users will probably not setup a TOR(-style) network themselves. That means you'll need to do it for them, so they still have to trust you. At that point, just not storing their IP address is probably easier.
There are still advantages to the TOR-style solution (you wouldn't have the ability to track users without resorting to backdooring), but the slowdown and extra complexity is probably not worth it in most situations.
There are still advantages to the TOR-style solution (you wouldn't have the ability to track users without resorting to backdooring), but the slowdown and extra complexity is probably not worth it in most situations.