One of the problems I see is that the TOCs have anarchic T&Cs in place with staff - such that there are always things that are jaw dropping. Bank Holiday Tuesdays being the latest "I don't believe it" kind of thing. Next thing you know, the press get hold of "railway persons don't work on Tuesdays" and the taxpayer and commuter, who works on that Tuesday is thinking "what the chuff", or "Sundays are optional" etc (but only on some TOCs).
If we're being honest, it's a mess. You wouldn't start from there. Every one of the benefits is negotiable for money, it always is. It'd be better to just agree what is appropriate for the 21st Century railway, nationally, set that in stone for new starters, and offer a buy-out of some of the irrational weird things like not expecting to work the second Tuesday after the Pentecost for current staff - but accept that Sundays may be special for some and allow that to be kept - for current staff. It'd take an incentive to get this through, but it'd be worth it for the railway.
And no, it's not right to reduce critical illness cover / policy, no-one ever knows when they'll need it. Removing it can easily increase costs as people actually want security and will favour employers that have that kind of protection.