Yes i also always got the impression that its supposed to be a flagship unit with its mechanic and heavily featured artwork/promo card, and it was a good card in general at the start. I feel like its splashability with only one frostorb required broke its neck, since it was decent in pve and a powerful stable in frost pvp, but it made the shadow frost deck overwhelmingly well rounded and strong.
I also really like your Tramble mechanic idea, i can imagine an epic feel charging into a camp with 4-5 knights knocking down small and medium units and doing considerable splashdamage, us