I think it's important to remember that they've tried a number of options in that 4th-line Center role, outside of "bandaid fxes," but have had a difficult time finding the right fit.
I can certainly agree that it's not ideal to turn this kind of thing into a habit, but one 2nd, 2 years in a row, is hardly selling the farm, and previous experiments in Smith, Moore, Aaltonen and Gauthier didn't pan out as well as they'd hoped at this stage.
Ideally, we fix this once and for all in the off-season (preferably for nothing more than money), but I think it's a little ridiculous to spend this much time and effort lamenting these transactions when you use whatever hindsight is currently available to us - We did have as close to "extra" 2nds as you could possibly have (having acquired 2 for Polak, who we then re-signed); Boyle helped us make the Playoffs last year; Plekanec was a big part of our team coming back from a 2-0 deficit to force a Game 7.
As long as every move made helps this current core of young players develop and be more successful moving forward, I can work with it. As important as draft picks are, they can't help Matthews, Marner and Nylander right now, so as long as we're not giving them all away (which we're not), I just don't see the big problem.