Worth pointing out that GNB gunblades, aren't actual guns, "the firing mechanism, emitting a range of magical effects by utilizing aesthetically imbued cartridges " courtesy of the ffxiv gunbreaker job guide. Garlean gunblades are both gun and blade. So no it would not be thematic in anyway.
And uptime or mobility, are basically the same the thing, get to back to boss asap so you can keep uptime, neither is mutually exclusive.