I agree there could be demand especially for the early flights and given Stansted Airport passenger numbers are set to increase. A class 755 might be sufficient for a half-hourly service south to London and an hourly service north to Cambridge calling at London Liverpool St, Tottenham Hale, Cheshunt, Broxbourne, Harlow Town, Bishop’s Stortford, Stansted Airport, Audley End, Whittlesford Parkway, Cambridge South, Cambridge.
I made the mistake of using a late flight (9pm) from Dublin using Ryanair last year, it was over 2 hours late for a flight that should've taken an hour! Just missing the last train that connected with a service that stops at Cheshunt. The taxi was £81! Luckily could share with someone going the same way, but overnight trains would've been really appreciated and useful and far more affordable. Especially as Harlow gets overnight buses and Stratford gets overnight coaches from both Flixbus and National Express. The railway should offer at least a basic hourly service by comparison.
On that flight, a group of people had to get back to Norwich from Stansted, I dread to think what they paid for a taxi!...
So overnight to Cambridge may be the right call.
In general, I don't understand why Greater Anglia don't run later trains on the WAML.
Last Liverpool Street train to Bishop's Stortford/ Cambridge is just before Midnight.
Neighbouring lines last departures -
Weaver Line to Chingford - 1:03am
Greater Anglia to Southend - 12:50am
Greater Anglia to Colchester - 12:46am
Kings Cross to Hertford North calling at Cuffley - 1:10am. Used this service a few times, always a good 10 to 15 people get off in Cuffley every time I used it despite it being a village!
Euston seems to have some very late early hours departures as far north as Milton Keynes and even Northampton on occasion too.
These all reach their end destinations between 1:30am and 2am.
Given the busyness of the line and the airport, it's need a better more suitable timetable and should be top priority if they are serious about increasing the usage of Stansted by 20 million passengers a year on top of today's ridership.