Personally, I am not terribly concerned about Showboating. Not yet, anyway.
First of all, this is the second set (spoiled) in an environment that is largely untested. Even as we see powerhouse cards like Showboating, we also see hard counters to the deck types which are likely to run them. As for myself, I am anxious to see how Gencon shakes out - we'll get a better sense of how the current competitive scene looks - which will then inform The Showstopper meta.
Secondly, Showboating is not a CP dump like Nic. It requires cycling cards, occupying hand space, succeeding pulls - turn after turn. All the while, the opponent (through intentional deck construction) will have opportunities to engage and counteract.
Thirdly, it seems universally playable. Spirit Fortress may stand to benefit most, but I think every outfit could build an interesting deck around this card. Maybe hardest for 108s? But they're awesome in other ways.
I understand the general anxiety about non-interactive CP accumulation. Perhaps it will accelerate a not-too-fun-to-play-against turtle variant. But I'm advocating for a "wait and see" attitude.