Well if you want to take the stopper, you go ahead, you might end up with better frequencies than existed before. I'll stick with the intercity train which will get me to London half an hour faster than the current ones do. Preferably with more capacity if someone pulls their finger out on remodelling certain stations.
The problem is that this dichotomy of "stopper" and "intercity" is only imposed on us by the low performance of the classic railway.
The UK is small, exceptionally small.
LGV Sud Est gets you to Newcastle. LGV Mediterranee gets you to Aviemore. Almost all of the traffic will be concentrated on short journeys by the standards of European railways. HS2's LGV plus station approaches concept is fundamentally unsuitable for this environment.
A high performance stopping train, built on modern infrastructure, can still beat the classic line.
Roughly 170km London-Birmingham via the M1 corridor, five intermediate stops for six jumps total. Each jump averages 28km or so.
Based on performance data available from Japan (on a 300kph railway), the end to end journey (allowing 60 seconds at each intermediate stop) would be around 71 minutes.
This beats the WCML but is slower than HS2s notional journey time. However, our primary goal is
supposedly to relieve the classic railway, so ultra fast nominal journey times are less important.
A line that continued north on that basis would still handily beat the classic railway to Manchester and Leeds and essentially match it to York.
Also if all trains stopped all stations, you could just run all 18 trains per hour all-stops along the trunk, as HS1's domestic services do.
Is 71 minutes 18 times an hour much less attractive than 49 minutes 3 times an hour?