As someone else has said, I would personally rather any halftrack comes as-is, and without an infantry squad inside it. I'd rather have the option to build whatever infantry/the HT separately, rather than have to get both when I only want the HT.
Ciuld always have the HT buildable in the HQ as well, but I think it would be neat being able to have access to the unique upgraded pgrens and grens in other commanders, but limited access.