If people decide they're not going to look at another piece of media or another article/interview, then sure. That's unreasonable. But no one here is going to do that, even if they say they are (unless they already had complete apathy for the Strider brand, in which case it still doesn't make a difference).
People should complain right now if they want to because this is the best time to get your voice heard. And yes, complaining in public forums, complaining in DH forums, complaining on Capcom's forums... it all matters. It creates buzz, either positive or negative, about certain aspects of this upcoming title.
And people can continue to bash Double Helix because, again, they've made shit. Maybe some of it was out of their control, but it's still in their closet. With regard to KI impressions, everyone that tries out a new game, especially one with next gen graphics, will probably be smitted at first. People acted that way with SFxT, too. I'm not saying KI is the same, but I'm also saying that positive initial impressions don't really hold as much weight anymore.
I think pre-release pre-emptive negativity can be a very good thing. There are plenty of public forums that are probably gushing and won't contribute a lick to making Strider a better game.