Any major city station that's not served by a modern railway (e.g. Nottingham, Sheffield, Bristol TM, Birmingham MS/SN etc.) is clearly among the worst and an embarrassment to the country.
No commuter or intercity journey should be made using obsolete, environmentally disastrous fossil-fuel based "technology" in this day and age, except possibly where extenuating circumstances require it (e.g. the impracticality of modernising the Dawlish sea wall).
Apart from that, Birmingham New Street is still awful. The refurbished shopping centre above it is nice, but hardly relevant to a rail traveller. The new "spread out" layout of station facilities is unnecessarily confusing and maze-like (obviously for "retail psychology" reasons) and the signage is woeful. Anyone spending more than a minute or two at platform level may as well be smoking 20 a day, with all the choking diesel fumes (which have no sane reason to be there; see above).