Washington already has arguably the best big man rotation in the league.
It'd be a pretty poor argument, but you can argue about anything I guess.
All right, well then let's hear your alleged strong argument against it. No need for drive-by disses on people's opinions, at least tell people why you think their opinion is wrong or stupid.
Gortat is on the very short, almost non-existent list of good two-way Centers in the league right now. Nene hasn't shown any signs of slowing down in past years, he's still top 10-11 among PFs. They are the biggest reason for WAS being 5th in DRTG and 8th in DRB%, keeping them with the 2nd best record in the East all season long. Throw in Humphries and Seraphin who are extrememly solid, and Gooden/Blair as reserves. Adding KG simply doesn't improve their rotation much, all it does is give them a better injury replacement on the 3rd string (and I don't think that's nearly enough to make a trade).
Then all you've got is the Hawks who have nobody behind Horford/Milsap, Memphis who has nobody behind Randolph/Gasol, and Dallas who doesn't have much behind Dirk/Chandler (Brandon Wright is serviceable).
I think what you meant to say is there's basically 25 poor arguments around the league for best big rotation, and then Washington in the argument with 3-4 other teams.