What you saw is true.
Anything like the Juggernaut we're used to would be too hard and expensive to put on the big screen. And it also would be next to impossible to explain the whole Gem of Cyttorak thing without alienating tons of people who don't read comics. Thus, he's just a large mutant with a battle suit.
Personally, I don't mind, as long as they stay true to the spirit of the character. And if not, we can just forget about it and be relieved it's not canon. 🙂