Blackhawks fan here, I come in peace.
The Hawks have 12 players signed for next year at $49.3 million.
http://www.capgeek.com/charts.php?Team=11
If the cap goes up to 62.5 million (which seems likely given a $375 million beer deal, a new TV deal, and absurdly competitive playoff races) that leaves $13.2 million to sign 11 guys. That doesn't sound that bad at all.
As for Seabrook's contract, I think it is bargain as long as he continues to perform at his current level, which seems likely given his age. Frankly, I'd much rather have him at 5.8 x 5, than something like 5.3 x 3 since that would mean he would be be demanding another raise, this time with a higher cap, in 3 years time.
Let's face it, hockey is growing in popularity and the cap is going to go up and up. I'm ecstatic that the Hawks have their best, youngest players locked up to long term deals in this time of unprecedented growth.