I feel like I've got a more clearly defined idea in my head of what the next five years will be like, though this could just amount to wishful thinking:
2020: Crossroads renovation and Carolina Harbor expansion. I'm thinking Yo-Yo finally leaves. It won't be removed from the ride closures list until daily operations start, and it's redundant with two other similarly-sized swing attractions in the park. I think the area behind it/part of PvZ's queue gets replaced with an Antique Autos attraction similar to KI's.
For the water park, a new slide or slide complex that will require the reconfiguration of the lazy river, or just expand into the area where TR's turnarounds used to be.
2021: RRR's plot of land gets taken over by something like
Forbidden Frontier at Cedar Point. Perfect way to re-introduce Frontier Outpost, and it's a relatively cost-friendly investment.
2022: Floorless conversion of Vortex. General infrastructure improvements and miscellaneous park upgrades.
2023: 50th anniversary. This is the year I see as the next "landmark year" for Carowinds. I'm not one who thinks parks add coasters solely for the sake of anniversaries (because they don't), but it will have been four years since Copperhead Strike. So I'm predicting a new coaster/area in Dinosaur's Alive's plot of land, along with a renovation of the south gate.
2024: This is hard to predict, only because by 2023, the park will be more or less "complete". So maybe it will be a small to mid-sized flat ride, or even something with Planet Snoopy. Guess we'll just have to wait.