Personally, if they said they want to sit on their asses and get on with their lives, I'd still be happy for them! They deserve the rest after being at it for ten years!
But, if something was to be released, if it was a large thing, I'd say multi would be nice to have. It'd be nice to fly with my buddies who're into WC as well as well as making missions for multi.
Then again, if it was something small, I wouldn't mind being able to cloak my fighter. Always been a big fan of cloaking and sneaking around.
I too would love to see new ships or even a Border Worlds or Nephilim campaign sometime down the line, but I expect something of that calibre would require another ten years of devotion to see through and the way I see it, the WC Saga team have more than earned their rest (and ten years of catch up sleep!).
I'd really like the possibility of playing multiplayer on servers that can be set up by everyone. A kitty campaign would be nice too, but that'd probably require much time. But mixing both - playing multiplayer with some players being terran and others kittys, that would make me feel like I'm in heaven xD
Sim missions are fairly easy to do. You don't need to have good FRED skills for that.
Actually flying around cloaked and shooting stuff isn't half as much fun as you think. I tried it and was a bit disappointed.
I'll include a demo mission in my mod anyway, and try to make it an interesting one.
As soon as my mod is released (which could be as soon as next month for the first version, some weeks give and take) you will have all the assets available for building a Kilrathi campaign in the WC3 era.
I changed the interface, created medals, created some generic wingmen including voices, made all the Kilrathi ships and weapons available for the player, included a Kofar-class support ship and the cloaking for player and wingmen.
So that will already be there.
What you need is a story and somebody who can use the mission editor, which is not hard to learn. In fact you can create your first working missions on day one, there are tutorials for that and a lot of nice people who can help you.
My own Kilrathi campaign will be released with the mod (or shortly after that) and show how it could work.
So if you have a good idea what could be done, it is in your hands!
Go into the modding forum, create a thread with your ideas and start brainstorming. There you can find people who want to do the same thing and you can form up a team.
(You can always do it alone, but I can tell you that doing that alone is a lot of work. I know that because I'm doing it almost completely alone.)
Aim low and create some simple missions first. Then plan from there. If you want to you can make it happen!