Waverley's taxi rank used to be inside the station, with level access for passengers from the main platforms (though not the ones "through the wall"). It worked pretty well. Since the last reworking of the platform layout (or last but one, or the one before that...I lost count) the taxi rank is now on Market Street which is an escalator or elevator ride up from platform level and IIRC also requires negotiating a flight of steps to get to street level from the walkway (memory suggests that there may be second lift as well).
The new 'rank' is much smaller, you have to queue in the open, which can be not very nice in Edinburgh in the winter, and it seems to be much less frequently served by the cabbies (some of whom seem to prefer to tout for fares outside the Balmoral hotel on Princes Street, despite the fact that ranking is explicitly forbidden there).
Things aren't that much better at Haymarket, where the taxi rank is again outside, and requires you to cross the tram tracks and two lanes of busy traffic. Traffic light-controlled crossings are provided, but they seem to be pretty leisurely in responding to the buttons being pressed - it's not uncommon for people to be able to cross reasonably safely long before the green man comes on, though that can be less than ideal if you've got heavy luggage. Then again, it's think it's pretty much always been like that; it's the significant downgrade of the facilities at Waverley that stands out.