In case it wasn't obvious enough from the fact that I posted this poll, I support switching to GPL. It's not a perfect solution, but I went and jumped in the deep end when I tried to sort out things with the Android port that Yong Zhang made and put up on the Android Market and as far as I can see this is a pretty good solution.
My main fear, with keeping the license as it is, is that SNES9x will stagnate. It costs money to put up software on the Android Market, and it costs even more to put it up on the iTunes marketplace. If not for the lure of potential money, it might have been a very long time for any port to show up on the Android Marketplace (and there still isn't one for the iPhone/iPad/iWhatever).
Also, there's a lot of code available out there that's licensed under the GPL - utilities, libraries, all sorts of things, that can't be incorporated into SNES9x because of the licensing conflicts.
The current license is difficult to enforce. This has been proven quite pointedly with Yong, who e-mailed Gary Henderson for permission but not any of the other developers. I tried to get a hold of them; it's absurdly difficult. Their e-mail addresses have changed, most of them have next to no presence in the internet at large, and without being able to contact them, there's no real legitimate way to do a lot of things - which also results in people taking advantage of this and doing whatever they want, as long as they aren't caught. Even if they are caught, who's going to press the issue? Since the license is so dependent on being able to contact the authors, would anyone press charges without the go-ahead of all of them? Suffice it to say, this does not benefit the project.
On the other hand, the GPL is enforceable. There's a big organization devoted to this, the Free Software Foundation.
I would also like to raise the argument that opening up SNES9x to commercial use is beneficial to the project as a whole. A lot of people have devoted large amounts of free time to improving the emulator, but let's face it - money is a prime motivating force in this world. And if someone, like - say - a company that wants to release some shovelware makes some improvements to the code and sells their old SNES game on the market, it is required that this company release the source code to the public. If the changes are genuine improvements to the program, they can then be folded into the main SNES9x. Especially if it's a port to an entirely new system. The company has no legal requirement to recognize the SNES9x team, but hey - there's nothing keeping the webpage for SNES9x from saying 'We're what makes <insert port> tick! Aren't we awesome?'
Take a look at DosBox for a good example of this. A lot of old PC games are being sold on GoG.com and through Steam that run on DosBox. You wouldn't know it unless you either 1) look at the binaries or 2) go to the DosBox website, but they're happy to be the engine behind most of the old games being sold for the PC these days.
I probably have some more reasons I could throw at everyone, but this post is long enough as it is and I'm starting to lose my train of thought.
In conclusion though, if you all agree that this is a good direction to take things, I'll make the extra effort to track down each of the old devs and try to get their stamp of approval as well so we can make it happen.