RE: Light bulb moment
I've BTDT with my electric bike (Vectrix) - Support groups launched upgrade paths from Ni-Cad cells to Ni-Li packs, in addition to the battery swap, you needed a new on board charger (at £800-odd) the cell packs and a firmware update from a homebrew supplier. There are already stories of two users with bricked bikes due to the firmware upload failing. I doubt the Fluence will be much different - apart from having to run a new loom of HT wiring for a CCS socket, all this assumes you get the support from a knowlegable source - that won't be coming from Renault!
Faced with a working car with no Rapid charging, and potentially bricking it leaving it only of use for spares, I have no interest in changing what works, its not as if it will make the car do more. You mistake negativty for caution... that's a whole different ballgame. I like my car too much to risk frying it prematurely - and if you don't have an inrush controller in your toolkit, I wouldn't even bother.