Both rides were classics, but they did put the guns in, so there is evidence that they are willing to change a classic. The Diving Bell is now no more than an urban legend, albeit a true one, that lives on in our memories as the most creative of all of SDC's attractions, and then they traded it out for a substandard innertube river ride that pales to most others in the industry. I understand the attraction to the oldies, and I would be shocked to find FitH was upgraded to animatronics or changed to another theme, but I would have absolutely no problem with a similar upgrade to FM. It would bring life (pun intended) to an attraction that rarely has the appeal to attract a line of people, and would thus decrease the long lines at some of the more popular rides. But no, they cannot remove either of these without drastically changing the mood of the park. Each ride is a classic, and each presents a romanticized view of an otherwise dark subject.
Meanwhile, Disney has used dark rides to their advantage and has proven that lighter subject, darker subjects, and everything in between can be presented in a "dark" ride. Some can even be changed with the season or every few years to keep a return appeal. Dark rides are my favorites, and I long for the day that SDC turns to some new and unique dark ride subjects. I would love a ride based on the mind of Twain, and I've pitched some others in other threads.
That said, they have made some improvements on FitH and FM in the past couple of years that have immensely improved the appeal of these rides, and they absolutely must fix features on each so they work correctly. At no time should a feature be down for an extended period, and the collapsing bridge is crucial to a major drop. I can't even believe this type of a thing doesn't fall into their yearly repair budget.