The changes around the Commander format are really having an interesting effect on the market. Fortunately, Pioneer and Modern are also making sure that things are moving.
Have Red cards in general come down in price since the ban? There's a view in my group that Red was already the weakest of the 5 colors. And with Dockside gone, now Red is even further disadvantaged. So, we're expecting to see even fewer Red decks, which ought to mean that the price of other good Red staples would slide.
Now, this is working out great for me - we sometimes play a Commander variant we call Crapmander, where no single card can be worth more than $5. I was just able to build a Crapmander mono Red deck that I'm quite excited about. From my little world, it sure seems like there's some REALLY undervalued red cards below the $5 point. Just curious if that's just a 'me' thing, or if the whole community sees it too.
I think it's too early to see much of a shift imo. I think most people aren't playing Dockside and if they were they're probably not disassembling their red decks because one card got banned.
When a card gets banned from comp 60 card formats, people are going to sell off the rest of the deck since there's no point in keeping it around and they're probably putting up 4 copies of each card. Commander has 1/4th of the stock and people generally play decks they like as opposed to only the best decks