*Extra lines and signalling modernising on the WCML
What about the ECML, and to a lesser extent the MML, which also benefits from HS2?
*Focused funding in regional hotspots
What do you mean? Things like the Trans Pennies Upgrade, which is already committed? Or like NPR which is rumoured to be given the go ahead? Both of which are in addition to HS2.
*Reflect actual passenger numbers in timetabling to make traffic flow more responsive to actual need (of you like, make timetabling smarter)
You mean like cater for the circa 4,000 passengers an hour in each direction which use ICWC services, which is due to rise to 5,000 within 10 years.
*Use alternative destinations than Euston
Like where? Kings Cross, in need of more capacity, relieved by HS2. Waterloo, in need of more capacity relieved by Crossrail 2. Paddington, in need of more capacity, relieved by Crossrail. Liverpool Street, in need of more capacity, relieved by both Crossrails. Marylebone, has some extra capacity for longer trains by converting from loco hauling coaches, but not a lot. At Pancreas, in need of more capacity, due to get longer trains, again not gaining much.
Where else could London bound services go?
*Invest in high-speed internet
Current average broadband speeds are ~50mb/s with some reports suggesting that this could nearly double to 90mb/s if everyone opted for the fastest available speeds that they could. However even at 50mb/s that's more than fast enough for most office environments. The problem is not everyone have jobs which are suitable to be able to work from home and even those which are there's often reasons why they wouldn't find it practical (such as no work space, family, etc.). It also doesn't stop people from going and visiting family.
Even with the increase in speeds of broadband (2009 was ~5mb/s) the demand for rail has grown not gone down. How much faster does it need to go before we're going to see rail travel drop off?
Anyway, even if it does least to less travel wouldn't it be better too significantly cut the amount of road travel which people do before putting limiting factors in the way of people going by rail?
*Accept that building new railways aren't always the solution
I accept this already, there's no way that building a railway line between two towns of 10,000 is going to be viable, even a town of 10,000 and a small city of 150,000 (with no intermediate stations) would be viable
*Accept that London has enough investment and should get not one penny more
As I've pointed out above (previous post) the trains into London and many out in the morning peaks are full, the roads are full, that basically leaves flying as the only viable option for significant option of we are not going to invest more money (and even that's not going to work very well if you can't get to/from the London airports.
The thing is that HS2 also massively improves links between Birmingham and Leeds, York and Manchester. As well as provides extra capacity for local services to/from those stations. If you are going to stick by your promise of never using HS2 I think that you should also commit to not using services which are created or are lengthened by the creation of HS2 (good luck with that, in that it's likely there's going to be a lot which are).
P.S. I'm not the first to explain why your solutions don't work, but feel free to come back on anything I've said.