Really the requirement should be a 1.5C charge rate, rather than a kW rating.
Take the B Class Mercedes, which I honestly believed was going to be the first non Tesla car that would be able to use the network, with a 36kWh battery capacity it would struggle with a 2.5C (90kW) without hurting the batteries. If it only used a 50kWh charge it would still occupy a bay for the same length of time as a Model S.
My hunch with the Mercedes is the price points didn't work out. £2000 as an extra on a £30000 car is quite a difference to £2000 on a £50000(+, who orders one with zero options?) car.
I have a 60, and I'm not prepared to pay for Superchargers, they aren't on my normal routes yet (the nearest is 70 miles away), and I only use the car for my commute, or "in range" journeys (which in the UK is most
of them if you live in the middle of the country). This price/value equation becomes an even bigger problem for cheaper EVs
Retrofitting is going to cost me very little extra due to the taxation treatment I can apply, so I'm just going to hang fire until they become more compelling for my use, (or I trade my car in for a P85D in a couple of years time
)