Is that Andrew's reasoning behind Salt leaving? His Wikipedia biog has no links to Manchester ...
Probably just a Man U supporter.
City, actually !
He lived in Manchester before moving to Barbados when he was a boy, and has family there.
Andrew said he and Jordan wanted a change of scene.
IMHO, neither of those moves necessarily points to there being deep problems at Sussex.
A less dramatic explanation would be a widening gap between the test ground (or 100) counties and the others.
The Richard Halsall email quoted by Gwylan, does point to problems though.