UPE is awesome and I really appreciate your effort in making this. I just keep thinking that it is pointless to buy something if I even haven't able to complete one project without deciding I, however, can't complete it in some kind of reason. I think it is the best time to buy UPE and Game Maker Studio 2 when IGP will be done and when it may be more beautiful to improve it by making something or changing something that PB does not allow.
I personally think that before IGP completion PB is powerful and easy enough to be satisfied with it in PB limits, however, and you really can take it as a compliment.