Lou should do his best to retain Lee. Yes, he's 28 but he doesn't have as many NHL miles on him as other players his age. He really only has four full seasons under his belt. IMO his style of play - big body in front of the net with a great scoring touch - is the type that has the most NHL longevity - he doesn't rely on speed and quickness to earn his keep. He is a big, strong, physical goal scorer - with most points coming in and around the net.
I hope they push for a 4-5 year deal. 6 years would be tough to swallow, but manageable with a reasonable AAV hit.
I think they trade Eberle at the deadline - he is likely replaceable with a younger option. Not sure what they'll do with Nelson - depends how he plays under Trotz.
Some people are penciling in future lines with Wahlstrom, Dobson, Bellows etc... last I checked none of them have suited up for an NHL regular season game. I can go back in this forum several years back and find people penciling in Dal Colle, Strome, and Reinhart with the same anticipation.
Nobody has a crystal ball for the future of these prospects - when you have a known, low-risk option in Lee, along with plenty of cap space, you lock him up.