Not really even sure why they banned paradox engine. Just from our playgroup, we almost never saw them except in rare cases of something degenerate. I haven’t seen someone else play one since dominaria released and someone played it in their fresh Traxos deck (also the only deck I have one in and I have nothing to combo with it, it’s just a win-more card more than anything). Sucks since it’s not really used elsewhere the value is shot to hell. Our LGS wouldn’t even take the masterpiece one we tried to trade in. It’s a good, powerful card, but there’s so many more combos out there that they don’t give a shit about that I don’t get why engine needed to get blasted.
And yeah bringing back painters servant without doing something about grindstone is stupid. That’s someone out of the game as early as like turn three or some shit, not counting if you ramp earlier into it. I don’t think anyone’s really going to miss Iona, but I don’t think it needed banned (except now that painters servant was unbanned).