While I certainly wouldn't want them to start that lineup, I don't see why people are so down on it for short periods of time. First of all, I'd ask, prior to his injury last year, did KG really show any dramatic signs of slowing down athletically? Because I certainly didn't see that. Second, it's not like Paul Pierce is lighting quick. Is KG really any "slower" than Paul in terms of lateral quickness? Third, with his height and reach, he'd be able to stand an extra step off of most 3s and still be able to alter their shot. And finally, given this team's talent distribution, I think it would make some sense to play KG at the 3 for 5-10 mpg.
Think about it this way. Pierce and Allen play 32 mpg. Daniels plays 25 mpg. If it's a blow out, obviously you can put in one of the young kids for the spare 7 mpg. But if not, you really have 2 choices (aside from playing one of those 3 more minutes).
1) Play Eddie House
2) Play KG at the 3
While Eddie certainly offers shooting (which is nice), he's also a huge defensive liability guarding players 5 and 6 inches taller then him. What's more, if those minutes come next to Ray, he's at a disadvantage guarding larger 3s.
Playing KG at the 3 would allow us to keep a tall player guarding a 2. What's more, KG would likely be guarding some backup 3 in those circumstances, largely negating the burden on him. Furthermore, by playing KG at the 3 for 5-10 mpg, it'd open up minutes for Big Baby to get some more PT, which he'll struggle to get if KG, Perk, and Wallace are dominating all the minutes at the 4/5.
Again, I don't think this is ideal. And if we had signed Bruce Bowen, I wouldn't be advocating this at all. But being that we have 4 quality bigs and only 3 quality swingmen, I'd rather see KG play a few mpg at the 3 spot and get Baby some minutes than have the smurfish House play the 2 and keep Baby on the bench.