This was just inside of the 20 year mark, but I don't know if it would have changed much. In August 2004, Scott Niedermayer got a one year contract via arbitration. According to this article, the Devils offered 5 years for 40 million but Niedermayer wanted 45.
One factor may have been the expiring CBA as nobody knew for sure if there'd be a cap and likely nobody anticipated the players taking the 24% rollback on existing deals.
After the lockout, the Devils offered Niedermayer a max AAV deal (7.8 million) but he took less to play with his brother in Anaheim.
Keeping Niedermayer likely meant Lou would avoid signing Vladimir Malakhov (3.6 million) and Dan McGillis (2.2 million). But perhaps there wouldn't have been room for Brian Rafalski either (4.2 million); Rafalski did the the team a big solid by waiting until Niedermayer made his decision.
Of all the draft picks, maybe the one Devils fans dwell on is Mattias Tedenby over local product John Carlson in 2008. Not sure if Carlson would have been enough of a difference maker in 2012.
And then one minor "what if" for me is that we had Anton Stralman as a PTO for the 2011 training camp as insurance in case Adam Larsson wasn't ready to make the jump. Larsson started off well but hit a rookie wall and didn't play much in the second half + playoffs. Journeyman Peter Harrold took a regular shift for us in the playoffs. I always wonder if Larsson would have benefited from another year of development and whether the difference between Harrold and Stralman would have been anything in the 2012 SCF.
One more hindsight decision that I would have considered was giving up the 2012 1st round pick (29th overall) as part of the Kovalchuk contract penalty. I wonder if Lou had an inkling that the league was going to alter the punishment as it ended up being that our 2014 1st got pushed down automatically to 30th. But as it was, the net result was Stefan Matteau + John Quenneville instead of the 11th overall pick in 2014. Then again our scouts weren't exactly knocking it out of the park, so who knows if we pick Kevin Fiala or Dylan Larkin and instead end up with Brendan Perlini or Jakub Vrana.