While I can understand the idea, the fact is that the Sharks prospect pool is especially poor everywhere in terms of top four or top six potential.
Among defensemen with realistic top four potential, we have Merkley, Knyazev, Laroque, Hävelid, and Fisher. Among forwards with realistic top six potential, we have Eklund, Bordeleau, Gushchin, and Lund, with Robins, Bystedt, Coe, and Wiesblatt having very small chances. Of the forwards, only Bordeleau, Bystedt, and maybe Lund have realistic hopes of sticking at center (Eklund really should be a winger).
Yes, it would be nice to have Lundqvist in the system, because Merkley has obvious warts and huge downside risk and Lundqvist at least gives us two bites at the young, pro-experienced, smallish, right-handed, offensively-focused defenseman apple (really three - Hävelid is in the same group, just younger). But trading Bordeleau is robbing Peter to pay Paul, and getting older in the process (Lundqvist is a lot closer to being "what you see is what you get" than Bordeleau is). In fact, it's worse - we have two centers in the system and four right-handed defensemen.
Neither are a lock to make an NHL dent. Both have chances to be significant future NHL players. All a Bordeleau-Lundqvist trade would do is weaken one pool to strengthen another, and the one getting stronger is actually a strength relative to the rest of the (overall weak) pool.
The only way that trade would make sense is if you are absolutely, positively certain that Bordeleau does not have any kind of NHL future, and given his obvious skill set and performance, I think that's not a good argument to make.