The platforms is pretty poor, but I'd say that the past 5 years are making amends. The 125 project, the wires to Corby/MH and additional semi-fasts, Derby untangling - and more four tracking. Hopefully this will continue (Leicester, Dore even might help) - as it's a very important line, and could be further used (Leeds and Manchester services on from Sheffield, or more XC potential)
Under BR, the service was horrendous. 2-3tph tops, into an under-utilized, fume-y, desolate station. With a beautiful, but neglected facade. Nostalgia is a funny thing.
One other point I would say is that the phenomenal success of Thameslink (plus boom of Luton Airport) gobbled up a lot of potential slots.