Burrows signed his deal at the trading deadline last year when he was sitting on a grand total of one 12 goal season, he didn't have a lot of leverage at the time and Gillis could have just shipped him out of town. Maybe he held a gun to Burrows' head, sign the contract or you're gone, remember, Burke said he was on the market . (although I heard that the package including Burrows and Bieksa was the counter offer, not the original one from Gillis)
Right now Kesler is a much more valuable commodity, it's hard to find big, fast, mean, point a game, 2 way centre that never gets outworked, $5 million is a steal for what he brings to the table...and he's still probably a couple years away from hitting his absolute prime as well.