I've made plenty of suggestions what to do with Frontierland. I think the link is still in my signature. But here's a more brief summary compared to the detailed versions:
1) WRE. But redesign it a bit. Maybe have the track similar to that of HKDL's upcoming Pirates attraction. Must be a ride to get wet on. Like a previous poster said, DL needs an equal flume attraction that gets you wet to match Splash Mountain. Load area inside the berm and show building outside the berm backstage west of Toontown- but shouldn't disrupt Circle D. I know there's a backstage building here, but I think things could be moved around.
The DL railroad would past a haunted/abandoned Frontierland train station and passes over the final drop to WRE (a simlar drop to Universal's IOA's Dudley Do-Right's final drop). Ride vehicles would be longboats commonly used on the Mississippi River.
2) I enjoy Little Patch of Haven. Leave it. Bring back BBQ.
3) I liked Discovery Bay before. But it doesn't appeal too much now.
4) For a dark ride, I suggest hiding it under a newly constructed Cascade Peak. One idea is like the rumored Woody's Roundup- but use "windwagons" as your interactive ride vehicle. Targets could probably be dollar signs, sheirff star badges, bullseye, cowboy hats... One storyline to follow was Toy Story 2's Woody episode. Another is to have guests as honoary deputies and help Woody, Bullseye, and Jessie roundup bank robbers (look similar to Home on the Range's bad guys in Buck's dream).
5) Second dark ride idea is to have a sort of "Justice League" for American Tall Tale and Folklore heros. People like Paul Bunyun, Pecos Bill, etc team up to fight the bad guys. Guests come along on their own "windwagon" to accompany the heros on their patrol. The climax has the guests caught in a tornado and the heros have to save us now before it's too late!
6) Other cosmetic/ placemaking changes that I won't get into.
7) A Western stunt show would be great to have. I don't think DLR really HAS a stunt show. So this could be a very welcome addition to the Festival of Fools area.
8) Disney could have whatever they do in FOF put in at the Timon parking lot tram stop inbetween DCA & the bus/taxi stop. Probably also the tram route between DCA's Hollywood Pictures Backlot & Harbor Blvd once TImon lot is not needed and expanded for DCA.
So really what I think is possible is to have 1 dark ride and 1 wet family friendly E-ticket flume ride. And still keep Big Thunder Ranch.