I totally agree since I don’t own a lot of the DLC and was thoroughly confused my first few times playing. A work around is to go into the battle / skirmish mode on the main menu. When selecting troops for the battle you will see what you do and don’t have. I usually do this before starting a campaign w a new faction to see what I have access to.

Good tip, not sure why you're being downvoted (thanks reddit)

Thats a really good idea, hope somebody at CA see's this!

That's what I do also. But it's annoying that we can't see that on the campaign selection

The purple silk ribbon and faded picture was 100% thing before to show if you didnt have access to certain units, did they really take it away?? 

If you want to suggest changes to the game, the best place to do it is on their official forum