There have been so many 'masterplans' for Stranraer over the years, including the crackpot super casino of 15 or so years ago. The Monte Carlo of Wigtownshire, aye right. As far as I know the 2014 one is no more likely to be seen through than that.
The local area as it stands looks like a case study in how not to do transport planning, or any other planning for that matter. A railway station marooned on a pier with no ferries, a vast expanse of waste land, apparently with no ideas behind it and for sale, marked out for long departed queuing vehicles between that and the town, and two wastefully competing ferry ports remote from any habitation or economic value half way up Loch Ryan. You couldn't make it up.
As far as I can see, the only immediate hope is that the town discovers some sort of Brexit loophole that turns it into a boomtown freeport. Sadly, knowing Stranraer's fortunes, Brexit will probably have the opposite effect on the peripheral gains it brings from the ferries.
I really don't know what to suggest from a rail development point of view. By all means move the station closer to the town, but the tiny increase in traffic that this would deliver in itself hardly justifies the investment. Restoration of Dumfries-Stranraer has been done to death on this forum, and the conclusion is that it's dead.
Stranraer needs to reinvent itself big time, but there's no evidence of a local wit or a will to do that. This is not a problem that the railway can solve.