I was very fond of tutoring my generals, so I payed attention...
None of my skills, ever got higher than 1, oddly enough. Almost like Larian wanted to do more to increase a skill, but decided against it and never bothered to removed the "1" designation.
Your generals do get more skills however.
Scarlet for instance, is mainly an infantry defense specialist. Catherine a naval offense specialist.
Following their stories, Scarlet managed to gain an offensive 1 skill, and Catherine tacked along an aerial bonus.
That's about it though... I think it all fell victim to budget-titis.