Would not trade Fischer for Nelson. I like the odds of Fischer improving a bit, and he's basically been a 15-20-35 player for us this year, so even if he doesn't improve, he's a useful player with his size and speed. He needs to bring the fire more often.
I like Nelson more than rt, though. He's got size and will use it. Plays C or wing. He's good for 20 goals a year with about 15 minutes of ice time. Yes, he takes games off, but we have the same problem with Fischer and Perlini, etc , and still find them valuable.
We need to keep taking baby steps. Guys who bring the sticky every game and also pot 20+ goals a year simply aren't made available very often, though obviously we should add one if he is. Our decisions right now should be based on if the guy brings an upgrade (even short term) to what we have now, weighted against cost to acquire and how flexible it leaves us if another add or a kid can make him redundant in the future.