Could the show survive another format change?

Well, that's an awful good question and I don't predict this happening anytime soon, however it's not an entirely unlikely scenario.... but extremely improbable, i just don't see it. Even so it wouldn't be a drastic change.

This really is a very good question. There are so many factors that must be considered.

First of all, I do not know whether the show would survive another big change, but, rationally speaking, I doubt it.
The Super Mix format (horrible name, btw) is far away from the original Millionaire. I like it but many fundamental elements were changed. If the producers revamped the show again now and took Super Mix as the starting point, the new concept would probably be just too far away from what people fell in love with. Unless it were a very good format, it would probably kill the show.

Should they go back to Classic Millionaire and went in a different direction, away from Super Mix, if would again largely depend on the quality of the final product, but viewers might rediscover elements they liked mixed with new ones. I'm talking about things like the Hotseat, the original music or maybe just slightly updated versions of the original graphics. But there are two problems with this concept that could be significant:
-It's unlikely that the producers will go back to Classic Millionaire. On the one hand, I doubt that they want to pay license fees again. And to me it seems like TV producers don't like to go one step back. They rather change a format 1,000 times than return to the original idea.
-Viewers get confused by frequent changes. They need some time to accustom to a format and lots of big modifications could scare them away from the show.
I'm not an expert so my thoughts on this could be totally wrong, but it's how I see it. I'd be glad if I were wrong.

I doubt that US Millionaire has many years left on the air, at least unless they start promoting the show more. I'm sure they could attract quite a few people if they showed that the show still exists. Meredith was on Ellen like three times in the last two years, I think, and she never even said anything about Millionaire. She could just say something like:"Hey, you know, I have this show where we give away lots of money, tune in!" That takes like 3 seconds, I'm sure she could squeeze that in between two sips of horrible wine. Or why don't they bring back former contestants? Isn't this syndicated Millionaire's 10th season? Bring back Kevin Smith, Nancy Christy and Sam Murray, show bloopers or do a Classic Millionaire-themed week with the original lifelines or God-knows-what. Really, I'm confident that the show would be watched by at least a couple more people if we from the forum came up with their advertising campaign instead of whoever does the job now. It's no excuse that a syndicated show just doesn't have that much money. There are lots of inexpensive ways to promote the show. And even if they spent a bit more money, it'd be a good investment if they managed to pull in more viewers.

But I digress. Basically, I think a change might work, but not if they diverge even further from Classic Millionaire. Furthermore, changing the game again too soon isn't smart either, IMO. I think that the problem lies in the way they sell the show to people, not so much gameplay. They can add a million tidbits, but. it won't be any good if nobody knows about it.

I'm an extremely nostalgic person and I'd personally love to see it go back to the classic format. I don't feel the tension build up anymore as it used to. When a person was half way up the money tree, you knew it was going to get harder and harder and suspense would build, but with the shuffle format, you have no idea what question the contestant is even going to get. It's not fun to watch when the contestant gets a really hard question as the first or second and zonk out on it.

So basically what I'm saying, I'd rather see it go back to the classic format if they were going to change it, rather than changing it into something completely different.