Maelstrom was, to me, like a low-budget indie film. They didn't have a lot of space or money to work with, but did the best they could with what they were given.
We talk about Everest or The Mummy at Universal being cool because you stop and go backwards...but Maelstrom did it first! Plus you got the basics of the adventure, vikings, trolls, waterfalls, Valhalla, polar creatures and then modern oil rigs and a nice village port at the end.
If you compare it to Fantasyland Dark rides of that era, it really is about on par with them IMO.