I've been lurking on these forums forever and this topic is one that I'd like to chime in on. For the record, I'm first and foremost a Street Fighter player, but I recently bout a Wii because I loved playing Smash so much. It's the only wii game i own. In essence, I'm a newb and don't know much. Normally, I'd keep quiet but in a case the problem extends beyond game play. What I say is assuming that MK is indeed decreasing attendence.
The one thing I want to say is this: Don't take for granted the popularity of smash and keeping its community, including the scrubs/average/non-elite players happy. Brawl outsold Street fighter4 3-1. The SF tournamnet scene is largely a niche scene and it in general struggles for attendence . Trust me, you do not want to be in the same boat as other fighters. Use the fact that Smash appeals to the masses to your advantage.
People before me have already said this, but have been largely ignored. Scrubs/avg smashers/are not irrelevant in this discussion. Elite players are but a fraction of the entire player base, but are reliant on smashers not as skilled as them to pad the cash pools. Try to see this situation from an avg joe perspective because without them, say good by to $$. If it affects them, it affects the elite as well.
Honestly, it really is that simple. Even if changes make absolutely no sense, if it is causing the scene to die, then action needs to be taken. I see people going on for pages talking about frame data and tournament results when the most important part of the MK issue is largely ignored.