I don't think he's as good as Kyrie. With that said, the difference in age really isn't that much (two years), and you can call it a wash given Kyrie's knee problems and Kemba's relative clean bill of health.
The real reason you do this, if he decides he wants to come here, is that he may be a better fit for Stevens's style of offense. When Kyrie's at his best, he's a good fit too -- moving the ball, making sharp cuts, playing within the team concept. But the problem was that Kyrie was somewhat inconsistent in committing to that style of play. (Would he have figured it out with time? I think so, but we'll never know.) Anyway, I see Kemba as much more easily pluggable into that system.
Are we now too overloaded with wings and guards? Perhaps. However, I don't see it as a problem for this season and wouldn't feel the need to make an urgent move, like for instance trading Jaylen Brown (last year of his rookie deal) for a big. Remember that the Warriors won a championship with the likes of Zaza Pachulia and Javale Magee in the middle. Going back further, the 90s Bulls won with the centers like Bill Cartwright and Luc Longley. Yes, I realize those teams had transcendent, not just great, players. But the point is that if you have a big who's active on defense, can body up bigs like Embiid in the post, and do some simple things like set picks, rim run, pass etc on offense, that's all you need. I also don't think Yabu and RWIII nothings; they should be able to at least contribute off the bench.
Sign a decent big with your MLE, add some vet minimums, bank on Hayward getting back to full health and some improvement from the Jays, and you might be onto something.