Yes, I think that another lockout would be a devastating blow to the NHL and much of the progress made since the last work stoppage would be in jeopardy.
The last lockout was not too long ago and it dealt a major blow to the league. Losing the television contract with ESPN was a bad thing for the NHL. They ended up being relegated to Versus, which did a decent job and has now become a part of NBC Sports which helps the league on the national level.
It would seem that a lockout of any length would hurt the league's standing with NBC, which is already suffering financially and looking for places to save money. In addition, a lockout would lower the leagues value in the eyes of other potential networks when it comes time to look for a new television contract.
The biggest hurt from another lockout would be the struggling franchises in non traditional markets. Fans in those markets simply find something else to spend their money on when there is no hockey.