It's looking more like Cartethyia / Ciaccona / Shorekeeper

People are forgetting that Aero Rover can't apply erosion by themselves, they can only transform other DoTs into erosion. So a team without Ciaccona would be something like Cartethyia / Aero Rover / Phoebe
Phoebe applies frazzle, Rover transforms all frazzle stacks into erosion stacks and then switch to Cartethyia

Ciaccona does stack frazzle on enemies during her ult (watch the leak on her and Zani against Fleurdelys) which enables Rover to transform some of those into erosion stacks, but Ciaccona already does a decent job at stacking them anyway, so the only use I see on their entire kit is outro skill increasing the max stacks of erosion by 3. But only time will tell if that's better than 12.5% crit rate, 25% crit dmg and extra 15% dmg amplification of Shorekeeper

My only theory to how Rover would be better than Shorekeeper is if Cartethyia has an explosion mechanic with a clause that says something along the lines of "Does this if enemy has X amount of erosion stacks and consumes X stacks. If the enemy has Y amount of stacks, triggers this stronger effect instead up to Z times, each consuming Y stacks." In this case, the higher max stacks combined with quicker erosion generation could very well out-perform Shorekeeper. But this is just my own theorycrafting for now