As others said, usually the starting city and endgame hub are discrete.

On a functional level, in terms of expansions, Crystarium loses points for not having a Crystal Bell, a feature you normally expect in a main city. Lorewise it makes sense, but that alone diminishes the value of its inn.

Kugane inversely seems to the most practical of the expansion start cities, with an aetheryte in a reasonable position and no loading screens between features. That said with today's machines, by the time you'd hoof it over the the markets you could have probably just taken the aetheryte to reach the Jeweled Crozier in Ishgard. They are both OK.