I've asked the Support. Here is what they said:

Hi! I've checked this player's logs. He receives different discounts on smuggler's den items and troops. He can receive the same discounts quite often since he is on 106-th level. The more your haven is developed, the less relevant discounts you receive.

Now, my personal experience: I'm used to The Wheel giving me nothing useful, so I stopped checking. I have the feeling that I keep getting the same things non-stop, but - in all honesty - weeks go by without me actually looking at it, so I may be missing some more attractive discounts.

Also, I didn't know this thing about haven level. It does explain why The Wheel seems unattractive to most of us old players.

Payote said:

On Golden Coast server I have had Skins for a solid month. This does me no good as I have the skin I want and I am not going to waste rubies on skins as they cost to much and rubies are outrageously priced in my book. FIX THIS PROBLEM PAYOTE cords 805/-520 thank you

Sadly, Plarium doesn't consider that a problem. I asked specifically for skins about a year ago, because it bothers me too, and I was told that the discount would go away if I bought all of the skins. 

Also, the Wheel constantly giving you the same discount is considered "normal behaviour" as well. The main topic for that is here.