This is all very 'purist'. While I recognise that it is not desirable for the ease of travelling to London to cause a 'braindrain' from the West Midlands or further afield, the whole point of building HS2 is to move demand off the routes where the fast services currently run. They have even ensured that the same operator provides the legacy 'fast' service on the WCML and the service on HS2.
If HS2 fares are out of line or different from those on the existing routes, people will see HS2 as something which is not for them and that will not move the demand from the existing routes which is what is needed. All you end up with is people saying "they have taken away our perfectly good service to London and made it slower forcing us to use HS2 against our will". People commute from Birmingham to London already.
As noted in this thread, people simply need to see HS2 simply as the extra fast lines on the WCML (and later MML and ECML) that happen not to be built alongside for well established reasons and not as something different.
The whole point of HS2 is not to do with moving passengers off existing services - you're confusing features with benefits. The point is to improve the UK economy and to re-balance it away from London and implicitly towards a more sustainable future. I contend that encouraging commuting, rather than business (and to a lesser extent leisure) travel, would run counter to those objectives.
Under my proposal people who commute from Birmingham to London would enjoy a similar service at a similar price to what they get today, but would have to pay more for high speed. But peak fares for one-off journeys would be less, probably from intermediate stations as well because they shouldn't be disadvantaged relative to the places served by HS2. This might in fact result in the situation where there are no season tickets on HS2, a commuter just buys five Anytime returns.
Perhaps the level of discount we've been used to seeing for bulk purchase shouldn't be so great, but people have been talking about that for the existing rail network for years as well as well.
It's difficult to do because people will lose out on an arrangement they have based their lifestyles on. Much less difficult just not to introduce the facility on high speed, as this doesn't disadvantage any existing travelers.
If fares are increased on HS2, I think they will be increased on the WCML as well - ie they could be higher but there won't be a differential. It is not in anyone's interest to have cheaper fares on the Euston-Watford-Milton Keynes-Rugby-Coventry-Birmingham International-Birmingham New Street trains than the Euston-Old Oak Common-Birmingham Interchange-Birmingham Curzon Street services.
The services on the classic line will be slowed down - that is the whole point.
HS1 goes to a different terminal in London from the classic services. HS2 goes to Euston just like the current service. There is a bit of a difference - it is just a way of building the bypass lines on the WCML (and later MML / ECML).
I agree in general that there should be parity of fares including intermediate destinations being consistent with the fares between HS2 stations. This suggests a cross-the-board cut in Anytimes. But for the reasons I've explained I would make an exception for seasons - not conceptually much different from the operator-specific seasons we have today.
