[panick21_]

Crossrail uses advanced signaling making very good use of the resource. They use platform screen doors for both improve safety and reliability but also fast loading and unloading. Seem to me these are all improvements and were the right approach for Crossrail. They didn't do everything perfectly but the system is pretty damn good and pretty damn successful.

Yes, infrastructure has gotten more expensive, and that is particularly true in the Anglosphere. But those problem don't have so much to do with the chosen design, but rather it operation and planning processes.

What actual parts of the design are actually bad?

[bluGill]

I'm not up on all the issues with Crossrail, but that trains cost too much in the English speaking world is well known and Crossrail is not exempt. Generally this comes down to stations that are much larger than needed and other things that appear to be justified until you dig deeper and discover they are expensive and the rest of the world does without just fine.

[panick21_]

Trains cost to much because like many other countries, Britain buys from their own manufactures. Because of the state of British railroading since privatization most of British rail manufacturing collapsed and only a very small number of manufactures are left.

Station being to large is a question of taste and priorities. Saying that such tradeoffs are not worth it is different then just saying straight up that 'the results are terrible'.