I had the idea of trying to recreate WC3 as a campaign for your mod, I haven't read so much into how to do it with HWRM , but I have spent some time in the WC3 walkthrough making notes about the types and layouts of the missions, and ships involved.
At least how I look at it, it certainly seams that it could be made within HWRM. The best way that I could see how to do it would be each WC3 system campaign would be a single mission within HWRM. This would mean that there would be 11 HWRM missions.
I haven't got too much left to do to my notes to finish them off, but I started to get a little put off as I started to look into the HWRM side, then life and time got in the way
However from what you say
@L.I.F. and it can be made quite simply perhaps it is something that I can try to get going again. If nothing else I can certainly share my notes.
And a bit of useless information - in WC3 there are a total of 702 enemy ships (not including the unlimited waves that are faced at Kilrah or on the loosing missions)
This was one of my initial ideas, but after a bit of thinking, it appeared less interesting than initially envisioned. The thing is that Wing Commander III is, first and foremost, a space sim, where your pilot defeats his Kilrathi opponents through skill, wingmates and flying competence. Such a thing cannot be properly reproduced in HWRM. After all, if we had the same setup as in the game, then just send twice or thrice the amount of fighters and crush the Kilrathi without thinking. Or if you are forced to send the canon forces, you would have very limited control over the actual fight and it would end up being uninteresting at best, frustrating at worst.
Then, it would be weird as the Kilrathi would only have half a dozen to two dozen fighters per system while it's a bit obvious that stuff happens to other pilots in WC III and Blair isn't doing all the Victory's flight missions. These would have to be considered all over the game and would each face the same issue as before.
Thus why I honestly think sticking with Heart of the Tiger would be a tremendous amount of work for a limited result. It could be done with the Freespace 2 engine, but at this point, why not do like Saga and add one's part to the greater universe?
HWRM is a RTS, and with coding work, could be stretched to the realm of a single player 4X. It should be treated as such: you are in Tolwyn's boots, or Eisen's, not Blair's, and the campaign should reflect it.
In a way, it makes things simpler for the design, as the first goal should be to tell a story. For example, before I settled on porting End Run, my idea was to follow the TCS Eagle as it stumbles on Kilrathi raiding Confed' medical supplies and transport to bring material behind their lines. As it follows the trail, it realizes it's not an isolated event and goes in a mission behind enemy lines where it finally discovers the lab where the Kilrathi designed their final bioweapons. The raid on it goes bad, and some Marines are unwittingly contaminated, making one of the destroyers a hotspot for the virus, but they get the intel. As they go back to Confed lines, they get intercepted by a Kilrathi dreadnought and manage to run away when the doomed destroyer rams the dreadnought, slowing it down a bit. Race towards Confed frontlines and they finally get saved by Border Worlds/Landreich forces.
Here, as you can see, we are centered around the task force, the capital ships, for which fighters and bombers are just a force projection tool, and tell their story. The thing is, there are a lot stories to tell about the fleet. The final days of the TCS Concordia, the fleet actions during the Battle of Earth, a hypothetical Behemoth run towards Kilrah, etc.
One thing I am afraid this mod will be bad to, however, will be to tell the story of a few pilots. I can create special fighter units that are better than the standard ones, and I did that already with, for example, Maniac's Excalibur for'the Confed, but once again, if a SP pits him against Kilrathi, there will not be much skill involved, just a bot flying against other bots automatically and winning through better stats.
In a way, we are talking about the difference between Command and Conquer: Tiberià Sun and Command and Conquer: Renegade. Both are in the same universe, but they cannot tell the same story because they are completely different types of games.
One could dream, however, of synchronizing Freespace 2 and HWRM so one player could give orders to FS2 players and see their actions reported straight into the HWRM engine, but unless someone gives me a few dozen millions and a dedicated dev team, that won't happen.
As a last item, I did port the first WC 4 mission in game, and it ended up being:
Go to Nav 1
When in Nav 1, wait for Blair and Maniac to kill the Pirate fighters.
Go to Nav 2
When in Nav 2, spawn Seether to attack and destroy Orlando.
Go to Nav 3
When in Nav 3, land on Bluepoint.
Go to Nav 4
End of mission.
From the beginning to the end, the entire player interaction is less than five mouse clicks.