I really don't see why this wasn't already done.
Now Tourism isn't tied to Culture as it was in Civ 6 and with how the Culture Victory works based on Wonders, I think now we have the additions of Happiness & Influence as "yields" you could make a Tourism Victory in a similar way to Civ 6 work for Civ 7 but it could be tied to Culture, Happiness & Influencers rather than just Culture.
I will say, whilst I appreciate the change in Culture Victory Condition to being Wonder Focused, it feels very short sighted and I'm not a fan.
Sure, I don't mind a Wonder Win Con, but not as a Victory Condition representation of the "Culture" yield.
If you make new Victory Conditions, and adjust them for every Age, whilst making the ability to select relevant VC's on Game Start return, I think that will be a good step towards improving the VC's.