I think it'll be a case of 'suck it and see'. Take Gants Hill vs Ilford. If you can currently get a seat on a train at GH, with it only having come from Hainault, sre you willing to sacrifice it for the risk of getting one at Ilford, with all those Brentwood/Harold Hill/ Romford passengers on board? Will partly depend where you live in relation to both stations, of course, and whether you require a bus to get to either. I don't think anyone knows, inc TfL, and it may not pan out quite as expected. That didn't stop TfL cutting the parallel 25 bus route recently at the central London end, which has presumably led to an increase in Central Line usage in the East London area just at a time when it should have been falling owing to Crossrail!