Yeah, I think a DK mine cart attraction can be pretty sweet without a ton of bells and whistles. Start off the queue going through Funky's Flights, as if guests "flew" into DK Island. Have a nice Funky Kong AA to give some info on the island. Then have the queue move through Cranky's Cabin (which is mysteriously abandoned), and upward into DK's Treehouse (also abandoned). Cranky's Cabin and the treehouse can be filled with DK series memorabilia. Soon after, we enter a cavern where we meet a Cranky Kong AA (complete with rocking chair)
who is basically sending us out in mine carts to look for DK and Diddy, who went out looking for their missing banana horde and never returned. Cranky can also provide safety info via voice over in the station.
If the queue stays elevated after DK's Treehouse, the station could also be elevated and start with an early drop, with a lift hill mid-course. Throw in a few mine carts with DK/Diddy in them, a few carts with Kremlings (the crocodile enemies from DKC1), a few sharp turns and sudden drops, maybe some scenery gags - perhaps a slower-paced pitch-dark section where the cart's headlamp is the only source of light? Some "near misses" with an oncoming DK and Diddy could also be fun. The barrel "blast" element mentioned should totally be included somewhere - it's genius!
But yeah, it doesn't need to be super-flashy and high tech to be a great ride. A couple of nice AAs throughout the experience, some immersive jungle and cavern theming, and a few clever gags in the ride portion would be enough for me. Though I'm also a massive DK fan, lol.
ps - I hope they don't skimp on the music. Iwata once said that the original DKC soundtrack was one of the few video game soundtracks he kept on his iPod, and for good reason I think. I better hear some
DK Island Swing at some point, lol