You’d be lacking shortcuts obviously, and very rarely (mostly when you ask for it) you might be prompted to input a name for something, but almost everything else has mouse controls.
Now that I think about it, there are two keys that might be a bit inconvenient not to have, spacebar for emergency pauses (there’s a screen button but it’s harder to hit in a bind) and shift that let you queue an order instead of replacing the current one.
I am against all game design patents in general. You shouldn’t be able to file a patent on game mechanics, like no movie director could have filed a patent on, say, the idea of sequence shot.
Game content (art, characters, etc) is already protected by copyright. Patents have absolutely no business in this.