Yeah, I would be one of those guys that frustrates you. I put a lot of effort into my drafts, so it's a combo of wanting to be right and being stubborn, so I usually hang onto my guys. That plus years of being on the wrong side of trades, and I have learned that I am usually better at drafting and waivers than I am at getting fair trades. I will trade a couple times a year to shake things up, but trading isn't what makes FF fun for me. Like you said, if it's short bench and there are people on waivers, it makes it even harder.
Most of the time those 2-for-1 trades that you claim are "helping" them usually isn't the case.
I do wonder how much dfs is pulling people's interest away from their year long leagues as far as trades and activity go. I know I have gotten a little worse about it, and have been less likely to putz with my teams via trade since I have been doing dfs the last couple years.