This is how RUG should probably just function in essence, and I agree that Thought Scour/Mental Note are bad in comparison to just running Ponder. If you REALLY want a value card to help attain threshold faster, I would run
Predict, but that card is also in danger of being a 'cool thing'.
I think we can probably just cut Stifle, let 'good' players play around a ghost card that's not even in our deck, and add a basic island to the mix (19 lands total) to reduce Wasteland blow-outs.
I don't think 'Next Level Thresh' is all that great. Either you go full-on tempo with RUG Canadian, full-on control with UW Blade, or if you want to hybridize the approach you play UBG Team America. Without a solid removal spell, RUG doesn't seem like the best option for trying to go for the long game.