Uhh.. what? Have you ever played HOI III? The depth every mechanic had in that game was grand, many different angles, and variables and things pushing and pulling on each other.
What you just described is a strategy game, and or arcade game like Sid Meiers, or Risk.
In Risk you don't have to dealw ith every tiny detail, same with Sid Meiers. You wouldn't argue Sid Meiers is a grand strategy game. It's a strategy game, not grand strategy. There's a difference.
Grand Strategy means every mechanic has alot of depth, and multiple other mechanics pushing and pulling on each other. Again HOI III compared ti HOI 4, nothing further needs to be said or explained.