I don't mind a bit of Ken art here and there for a few cards in a set. Never really bothered me (In fact, I actually like collecting some cards like BCR Pikachu since it's a card with the official artwork of the mascot of the series, same with Power Keepers Zard). They're alright here and there as a one-off kinda deal, and have a bit of collectible merit if they are as such-but it gets kinda eeh when it repeats too much. That's just me though.
The whole deal with Tag Team Supporters not having unique art being an issue I can sorta get though. It's supposed to be a more special kind of card (at least they advertise it as such), so the desire TO have unique art is there. Hopefully the Full Arts are pretty exciting though. (Not huge on the Red and Blue one. I feel like they should have shown off their older designs that Sun and Moon introduced. That'd have been really cool. We've had their little kid Let's Go designs a lot already, it was fine for a moment, but now it's just underwhelming. Their older designs are fantastic in Sun and Moon, I'd have loved to see them be utilized, but alas. At least Team Rocket got really good Full Arts.)