Umm.... We already have a clear assumption of what Atomos may be utilized for and SE already has their sites on making Atomos an astral flow only summon. Personally, I dislike Atomos and would rather not have it but... anyway.

There's no reason for SMN to have there own warp. There's already an over abundance of ways to warp around that anything else will be redundant.

Need to get to a town?
Airships, Voidwatch T1 warp, synergy earrings (can be for pretty much every city, including Nashmau). Similarly in the past, Voidwdatch T1 warp to move between the three nations.

Abyssea NPCs in every nation can warp you to the maws. And again with past, along with already existing spells with WHM and BLM, teleport earrings, retrace scrolls, nation warp staves can easily take you to the past and then use campaign warp to get to your designated area.