Why not improve the situation somewhat by running more direct Glasgow Services via Kilwinning for faster journey times and improved connectivity for places south of Ayr?
Passengers have the option of changing at Ayr, or taking a through service via Kilmarnock. It is efficient use of rolling stock to provide high capacity electric services from Glasgow to Ayr, and concentrate diesel units on the Ayr to Kilmarnock route.
I recall that there once were some through Stranraer services via Paisley, but Stranraer isn't where the ferry connection is now.
If you look at the current 0704 from Stranraer to Glasgow via Kilmarnock it arrives at 0936, having left Ayr at 0830. An electric train leaves Ayr at 0835 arriving in Glasgow at 0926. Presumably, the Stranraer train would need to be set down only at Ayr if it went direct to Glasgow and a separate train would need to be provided for Kilmarnock. The current situation does seem more efficient, at the cost of some people changing trains in Ayr.