I don't see Flooded Mine leaving. I don't know what else could go in it's space. If anything, they'll completely redo the ride, but I don't see that happening soon. It's a classic, it's for the whole family, and it's one of SDC's signature non-coaster rides.
As for the comments about "You could go anywhere to ride coasters": that's true, but SDC has an exceptional line-up. Outlaw Run is spectacular and is, in my opinion, the best coaster in the midwest, if not the country. Powder Keg is incredible, and there is no family launched coaster that really compares. Wildfire is the least unique coaster at the park, as it's your standard B&M looper, but it's still exceptional. Thunderation is one of the best mine trains out there.
But yes, SDC is not just about the coasters. It's about the atmosphere, the theming, the friendliness of the employees, the craftsmen, the shows, etc. The park is the whole package. Is Flooded Mine a part of that package? Yes. Do I see it leaving soon? Like I said earlier, no. But if I'm wrong and it does leave, the park still has plenty of unique attractions to offer.