Ok so this is my understanding of what you are wanting to do:
You wish to make an official remake of DoW1 in the DoW3 engine.
You wish to add a new race to this remake, new units and change how some units work.
You wish to balance the multiplayer aspect.
You wish to sell this as a new game and not as a mod or expatiation.
If that is correct you would need Sega, Relic and Games Workshop to agree on allowing this to happen.
Sega because they own the DoW franchise rights.
Relic because you wish to use there own internal engine.
And Games Workshop because they own everything 40k.
If all of the above happens I have a couple of requests.
First I would like to see an official mod tools released with some documentation of what does what.
I would like to see all aspects of DoW3 kept in the game even if they are not used.
If this really does happen I would be willing to work part time on the project assuming it is official and I will be paid.
It should also be noted I started this a couple of days ago because me and some people where talking about how DoW3 was a good game but a poor implementation of Warhammer 40k.