So both those are reasonable if you read the meta right. I would also say that depending on what budget means (0-proxy vs 5-10 proxy vs infinite proxy) and also how much money is budget for you ($400 vs $1000 vs anything but power/shops/bazaars) makes a big difference in answers to this question.
In general I would tend toward unpowered blue deck over something like red prison in vintage? In a 5-proxy meta I would do this every time (3 mox/lotus 1 time walk 1 ancestral, and the rest of the deck is legacy cards).
Side note: I’m not sure why PO has never looked into 1-2 copies of Ascendency?
I think they just don't need it, and also the critical mass of free spells/cheap +CA spells to trigger it has gone down. When gush and dig were still legal along with 4 probe, there were some versions of the deck that could even hang with the shops deck of the time a bit.
Now, however, what would it be replacing that isn't already doing something better. Plus it pulls you into a 3rd or 4th color depending on the build.
The interaction with painter is way to significant to ignore. It may only see play in 1 deck but may push that deck from relative obscurity to a deck that can steal weekly challenges and league 5-0s.
This card has to be worse than red blasts 1-8 in painter though right? Do you have room for 9+ of that effect? IN all the old build of painter i played i struggled to play more than 4 and even with MM restricted I can't imagine playing more than 6-7.