I think that this is done and over with, a petition will do not a thing. NG is coming out on Wii-ware only, like it or not. Cussing and fussing is only going to make matters worse, blaming things on this company and that company does nothing either. Sure, it sucks, but leave it be. Nifflas has expressed how he feels and that is that. Is this Nifflas' fault, no. Is this Nicalis' fault, no. Business is business, and that is how things work.
It's bad PR to ignore a petition supported by potential customers, especially if all Nicalis has to do to satisfy the demands of the petition is to publicly provide a coherent reason for the lack of a PC version of the game. (Then again, if the reason given is "because we want money", then that'd probably be even worse PR.) Doing nothing in a situation like this allows a company to continue ignoring the demands of potential consumers.
I think most people are mature enough to respect the fact that the video game industry is, in fact, an industry, and most game developers want to make money. Maybe they looked at World of Goo's 90% piracy rate and thought "Yeah, let's not do that." "Because we want money" is a perfectly valid reason. (By the way, internet petitions are a waste of bandwidth and never accomplish anything.)
Most people who care about this game are just excited about it. The only people I've seen that are butthurt about it being WiiWare-only are on here, and like two people on NeoGAF.
http://www.neogaf.com/forum/showthread.php?t=353843
Regardless of piracy rate, World of Goo has been very successful- and that piracy rate doesn't apply only to World of Goo; it'd apply to any popular commercial video game release. Thinking that attempting to prevent piracy will increase sales is extremely wrong. Most people who pirate a game wouldn't've bought the game in the first place. (Also, there's probably some way to pirate WiiWare games. If there isn't, there will be one soon.)
And the "because we want money" argument, regardless of validity, doesn't make sense here. There's no way limiting the distribution of a game is going to make
more money.
I expect that anyone who has eagerly anticipated this game, and has a PC but not a Wii, will be at least a little disappointed- I can't see how you wouldn't be. (There would be very, very little disappointment if it had been announced much earlier that it would be Wii-only. The IGF site still lists NG as "WiiWare/Windows PC". That IGN article from February 4th still lists NG as PC/Wii.)
There's hardly anything to be lost by starting a petition.
And
of course there's a concentration of disappointment here. This forum (in its previous incarnation) was where Night Game was first hinted at, and the main channel for release of hints about the nature of the game. For over a year, there's been an unchallenged presumption that Night Game would be released for PC, the same as every other Nifflas game, and most indie games in general.