Its an interesting question as to what would satisfy an EV sceptic in regard to charging, I'm thinking nothing. Taking my real life example from yesterday (or maybe the day before, I forget). 20mins to fill my poxy roller-skate of a hire car with enough juice to take me about 370 miles (1.0 fossil cars and motorways don't mix).
We are already at the point where 150kw chargers are at the deployment phase, meaning a 75kwh car can go from 10%-80% in around 20mins. When we have EVs that can take you 300-400 miles on only the charge time it takes you to have a coffee and go for a pee or two, what more do you need or want from the tech?
No. It doesn't take 20 minutes to fill up your poxy hire car. It probably takes a couple of minutes - perhaps 5 tops. The other 15 minutes is spent faffing around getting there, waiting for the old biddy in front to fill up and pay, plus paying yourself. Most of that faffing is equally applicable to charging an EV vehicle so your 20 minutes for an 80% charge is actually 35 minutes under the same conditions.
Except if the old biddy is also filling up an EV, then it takes her 20 minutes (minimum) to dispense the electricity from the pump, instead of the 5 minutes it took her to actually work the petrol pump. So add on another 15 mins, and we're up at 50 minutes.
So lets compare 'pumps'. If you can fill a petrol car with 75L in (say) 5 minutes, that's 15L/min, which is 150Kwh per minute. Petrol cars are at best 15% efficient, so that's 22.5Kwh/min of useable energy. Your 150Kwh electric 'pump' is rated as charging a 75Kwh battery 80% in 20 minutes. So it pumps (75Kw * 80%) / 20mins = 3Kwh/min. If the motors are then 80% efficient then they're effectively pumping 2.4Kwh/min of useable energy.
We're talking spending 10 times longer actually at the pump filling up with electricity, which means to match the current petrol pump system you either need 10 times the number of charging points, or 1.5MWh capable chargers and batteries. Most petrol stations round here have 12 petrol/diesel pumps. They're going to need 12 1.5MWh chargers, or 120 150KWh electric pumps to match that capacity. That'll require an 18MWh supply to each petrol station. The new Hinkley point C is 3200MW, so could power about 180 such petrol stations.
And I'd oppine that its actually a lot worse than that :
1) I don't believe it actually takes anything like 5 minutes to physically put in 75L of petrol. But the process is so short in the overall scheme of faffing about that we don't really notice the difference between 2 and 5 minutes (unless you're late for the plane/ferry!)
2) Comparing 100% filling a 75L petrol car, with 80% filling a 75KWh EV is wrong. 65L in my Meega will get me 420 miles if I'm careful - which is less than 30Mpg. Plenty of other eurobox options will get me 40+ MPG on the same trip. A better comparison would be 80% filling a 48L Ashtray/Vectra. So 40L, which will half the actual filling time - though this is still swamped by the faffing time.
So I'd argue that once the actual filling time exceeds the faffing time you'll start to matter how long it actually takes.