To be perfectly honest i dont think HUY want to be in direct competition with DSA, that would be far too risky. I heard from someone 'inside' that they have said they are to keep playing to their strengths, strengths being IT/charter.
Though i dont believe they actively discourage lo-co ops i dont think attracting one is on the top of the agenda, its all down to money at the end of the day, HUY makes more money for MAG than BOH does, BOH's expansion being predominantly from low cost airlines.
The sun routes would work, i have no doubt, but a lo-co would surely want more than just the potential of operating to the usual ALC, AGP and PMI. A similar operation to that of Jet2's at BLK would be good and it is thought they are still looking at HUY for a base in the future, though the thing thats stopping them is not the catchment size more the demographics of the region.
All that said though, FR have proved that there is at least demand for low cost flights from HUY and maybe some potential lo-co will be watching closely before making that investment.
At least the core routes are stil there and growing KLM going 4xdaily, CFU and SSH with a full based a/c from XL next summer. You never know we may have someone else in by then.