While I agree that butt scooting is a poor product of sport bjj, I think the solutions you suggest are worse than the problem itself.
I hate pins being match ending. That just not bjj and removes ot further from submission grappling. It just removes any guard play as a viable option at all.
And similarly, not counting sweeps from open guards just makes it even more difficult to win as a guard player and discourages guard play in any form. It too extreme of a correction. I think there's a misunderstanding about what seated guard is in a functional sense here. It's a mobilizing guard, not a sweeping or attacking guard. It's for quickly switching from stand up recovery, distance management, and engaging to set up a full guarded position.
In every tournament with point values you are unable to sit to down with no grips. And in many you get a penalty for pulling guard at all. The sport already significantly favors player who use takedowns. Even IBJJF, which people regularly criticize, will not let you just sit in seated guard indefinitely. If there is no action then you get penalties and stood up. Takedowns are and have been the meta for years and as time goes on it only gets harder to pull guard without punishment, let alone sitting.
The issue isn't the presence of guard pulling in the sport. That's what's being missed. The problem is the sub only rule set. Sub only has always been where this shit becomes an issue. There's too few restriction on how you can engage and refs almost never punish you for being passive. The issue isn't sport wide.
The most exciting grappling formats, by far IMO, have been Combat Wrestling and ZST GTF and Contenders. In all of those, you see people starting from the feet and you see action on the ground reset if it stalls out. The feet is taken as the natural starting point and it is seen as the responsibility of each competitor to bring their man to the ground if they want him there. The standing opponent is always seen as having the advantage and impetus is upon the person on the ground to bring the standing opponent down to your level if you want him there, otherwise, the assumption--in those formats--is that if he's standing and your on the ground, you're losing. It creates certain incentives, inspires a level of dynamism and aggression and is just more aesthetically pleasing.
As far as pins, I think that is a crucial element that needs to be made more common in grappling formats intended to be seen as neutral grounds between styles, because without it, you remove the main objective of so many styles and thus take away their ability to really interact with practitioners of other styles. People can still play guard in formats with pins; its been done in catch-wrestling competitions and it has certainly been done in judo. It just makes it something inherently risky and thus--in my eyes--more exciting, which is, IMO, as it should be.
I love the seated guard, I love butterfly, I love open guard in general. I wouldn't want to see either one eliminated but I think a competitive format that maximizes the aesthetic potential of grappling would see people playing seated guard in more of a "hot seat", the way wrestlers in the days before back points, for example, where in the "hot seat" when they used elevators and such off of their back or the way a Nick Simmons in more recent times was taking a major risk to play the game the way he did.
BTW, I actually don't think BJJ per se needs to change. But I think if you want to create a grappling format that serves as a legitimate proving ground between styles and is truly entertaining, like Combat Wrestling so consistently was, for example, there's certain things you need to do. I personally think there should be formats that are considered "professional grappling" where an emphasis on entertainment, pushing the pace, engaging and taking risks is emphasized and on the other hand, amateur competitions, where it isn't about entertainment or an audience but just about competing. I don't think BJJ has to change but I do think that submission-grappling has yet to realize its true potential as an entertaining sport and the rules and format is part of that.
