I don't see why anyone would buy the "players have given up so much" line of argument. Yeah, they have given things up, because they've been making money hand over fist while most of the league loses money or barely breaks even. No shit they're being asked to give back some of their share of revenues, amongst other things. If they aren't willing to do that, then it's pretty much inevitable that at least a couple franchises will fold, and guess what, that means less players and less revenue to get a cut of.
As far as the CBA length goes, the players are stupid to try to argue for a shorter term. Everyone else, especially the fans, wants the CBA to be as long as possible so we don't have to put up with this bullshit again in 6 years.
Contract term limits I personally don't feel are necessary, either. So long as cap circumvention is fixed, I'm fine with letting GM's sabotage their franchise's future with ridiculous long term contracts that they can't get out of or bury in the minors. However! The reality is that the NHLPA is fighting for contract terms that only affect a couple dozen players, out of 700+. And that's really what it comes down to, the NHLPA can protest all it wants that they're fighting for the "average" union member who might have a 5 year career and make league minimum or slightly above it. But really the main bones of contention that the NHLPA has fought for are almost all about couple dozen superstars.
If the owner's last offer had been put to a vote by the NHLPA, we'd probably be playing hockey by now. Or it would have been very, very close. The 500+ "average" NHL players that don't have a hope of seeing 10 year contracts with 9 figures are NEVER going to make the money back from a lost or even abbreviated season. Ever. It's sheer idiocy on the part of the NHLPA to play with fire the way they have, because at the end of the day their membership can never recover the wages that have been and will be lost. They've already agreed on the revenue split, there had been an agreement on "make whole" money. Those two issues will ultimately determine how much money the membership makes going forward. Contract term limits have zero impact on that, other than further stratifying salaries with superstars making far more than the rank and file.