About GP on Artistry, I suggested the 33% on GWAM and removal of 50

gold on GP birth because the OP wanted to differentiate Artistry further from Tradition by decoupling

GP generation. The original discussion on a previous thread was only about decoupling

GA between these two trees, since you can have GA civs that don't have GP related bonuses (Brazil, Egypt, certain mod civs like JFD's Meiji) going for both trees almost mandatorily. While I think Artistry's focus points heavily on

great works, I don't think the tree needs to give up GP focus in order to decouple from Tradition's focuses. As long as Tradition shares at most one focus with Artistry, that's enough; Fealty shares the

growth theme with Tradition without locking the latter into it, and

infrastructure with Progress without locking it away from, say, Statecraft.
On a note, I think part of why Artistry is paired with Tradition so often also has to do with the former having no clear shared focus with either Progress or Authority. At the very least, Artistry could have one or two of its wide bonuses buffed, such as the scaler.
I do think Artistry is too slow compared to Fealty, since the most desirable aspects of the tree are on Cultural Heritage and on the finisher, with the latter even requiring a late Industrial Era tech on a medieval tree. Overall, I think Artistry could be buffed by having more of its bonuses frontloaded into the earlier policies.
Keeping the proposal simple and without the more controversial parts:
Tradition
Opener - 4

food (or more) in the

Capital instead of 2

food. +10%

Growth (or more) in all cities instead of +5%

Growth.
Splendor - Remove the 50

Golden Age Points from GP expenditure.
Finisher - Remove +25%

Golden Age length.
Artistry
Scaler - Buff to yields,
e.g. "+5

GAP and +1

Science per city".
Refinement - Gain "+2

Culture and

Production to Amphitheaters and Opera Houses".
Cultural Heritage - Loses "+2

Culture and

Production to Amphitheaters and Opera Houses".