Agh. Most of the issues you mentioned are fixed in the elite mod. Mortars? Check. Whirlwinds? Check. IG can certainly hold the line in that. and tanks now murder infantry.
I admit/agree that annihilate is a broken game mode. I think that is more the result of the AI being awful though.
If I don't need to deploy multiple squads of Guardsmen to have a chance against a single squad of Space Marines, not interested.

That site also contains very little information about Elite other than unit stats, such as a changelog or an overview of the general changes, and it doesn't even have unit stats for the IG, Eldar, Orks, and Nids.