This whole deal is arsewipe.
Scarlets and Ospreys are far more successful than the Dragons, who have a history of under achievement- whipping boys in a pretty sub standard stadium. The rationale is ostensibly to have a gogledd rugby region, splitting the country into the points of the compass. The only issue is the East and South, as represented by Dragons and Blues, are, in fact both East by any definition of Geography. Scarlets technically have a massive area out west to Pembroke and beyond that is theirs (IIRC they actually have responsibility for the north too at some stages), whilst the Ospreys have the highly populated county of Swansea right up to Bridgend, where I am pretty sure the Ospreys have played matches in the old Anglo-Welsh. So in the end, as it stands, it will be N/SE/SE/W, as Cardiff and Newport are practically identical in terms of geography. If they really want N/S/E/W then Ospreys, representing from Bridgend to Swansea, are a far better representation of South, and Cardiff a representation of East.
The only Pro 14 matches that get good crowds are the derby matches around Christmas and Judgement Day double headers, making this move utter, utter madness.
As for players being told they will move, it won't happen, North is just a different country, and attempts to make union thrive there are as likely to succeed as attempts to turn the north of England away from league.