Ally,
An interesting topic, probably because there have been so few links courses that have had significant makeovers, especially in recent years. And I think this is down to what Wade touches on, ecological issues. So many of these courses run through dune systems that have now been designated SSSIs (Site Special Sceintific Interest) and this would make any major work virtually impossible. Look at how the only two new authetic links courses I can think of that have been built recently (Askernish and Mach Dunes) by virtually nothing more than mowing the existing grass. I'm no expert but its possible that if a lot of these links courses hadn't been built through dunes way back in time, then even fewer of these rare habitats would exist as they would have probably been developed over by something less sympathetic than a golf course?
However, as this is a hypothetical discussion...
I agree with wade that some work at Royal County Down could really lift that course, at the very least do something to 17 and 18.
I can see Sean and Kevin's point about Burnham, but I think I'd rather see some of the flatter holes moved a touch closer to the dunes perhaps, rather than wholesale changes just to get the course more amongst the big dunes.
How about Saunton? 2 good courses there, but I would much prefer to improve the quality of the East course and then maybe have a small relief nine holes, if by using some of the land from the West course you could really improve the East (to Open Championship standard perhaps?) then is that not better use of the land?
Cheers,
James