I like Calathes a lot, and if he goes anywhere in the early 2nd he'll definitely be a steal. There's a lot to like--he's only a sophomore yet he possesses an extraordinarily high skill level in terms of his passing ability--it's just a natural gift with his ability to dictate tempo, control ball movement and make the right passes. That part of his game will undoubtedly translate well to the NBA, and teams that like big point guards (the Warriors and the Lakers, for example) will really appreciate the height that goes along with it.
But he's not just a tall passer--I know some have reservations about his streaky shot, but he's up to 48% FGs and 39% 3FGs this year, so he's definitely improving. I don't think he'll be a sharpshooter by any sense and his overall FG% will go down due to athletic limitations, but I think he'll manage well enough here--he's smart, savvy and crafty, and knows how to exploit offensive situations. He's also shown rebounding ability and even triple double ability in college, and that alone should entice many scouts; I don't think his rebounding will translate, but that makes him all the more interesting.
His defense has been chastised all around due to lack of footspeed and athleticism, but he's competitive and shows a solid knack for getting steals. I don't think he's as bad as he's made out to be here, and while he'll most likely be a liability, I think he can develop some smarts to cover up for his weaknesses.
So overall, his offensive game is really 1st round material, but his defensive deficiencies might bump him back to the second right. But I think the youth (he's only 20), height/passing combination will be too hard to pass up for many teams--I know Europe has been a hotbed for creating tall PGs in recent years, but to have one do this against good NCAA competition should give him some points in his favor. I keep thinking back to a taller Luke Ridnour in regards to Calathes (and Ridnour went in the late lotto), and while I don't think there's much in terms of great upside with him, I think he's the type who can contribute over time as a tall orchestrator of sorts.
As for the Kings--I'm sort of split. I mean, if we could get him at #31, go for it--I like his talents as a unique tall PG who actually had triple double credentials in college, so clearly his skill level is high. The passing and perhaps the shooting (with some more work) will easily translate in the league, and that in combination with his height makes him easy to choose in the second round. And we really need that orchestrating point guard who can playmake. But the defense--again, we really need a defensive point guard out there. For that reason, I'd rather prefer Darren Collison, even though I like Calathes is more talented--but Collison can hit spot up J's well, playmake solidly and play defense well despite giving up inches. But again, in the second round, he's probably one of the best players available by then, so he may be worth it. I also like Sergio Llull from Real Madrid, a fairly athletic 6'3" combo guard with good shotcreating skills and some potential defensive ability/playmaking skills. I wouldn't mind stashing him in Europe for a few years to see what rewards may spawn from him.