Yes, as players get older, teams often look for ways to move them in order to make way for players that are younger. The younger players generally have more years in which the can be of value to their team. The trend to younger players is not necessarily new and will continue.
Yes, the Stars should have traded Jaromir Jagr to the Bruins. The Bruins are a totally legit team and Jagr will do great things for them. He was undermined with the Stars and did not receive the appreciation he most certainly deserved. Good things are to come for the Bruins.
Bias out front here, I'm a Bruins fan. This trade made sense for Dallas, they're a garbage team that is going nowhere and they got a lot back (including a potential 1st round pick) for a 41 year old player. There wasn't much reason for them to not do this and capitalize on what they had.
The Dallas Stars should have kept Jaromir Jagr. He is an extremely talented ice hockey player, who not only won the Stanley cup but also an Olympic gold medal. Instead of trading one of their best players, they should have traded someone less competent. This trade is a detrimental decision for the team.