Niedermayer. He was one of those type of defenseman that could eat up huge minutes and you might not notice him much - that’s always a good thing. A lot of what he did best didn’t show up on the scoresheet. Later on in his career, he added near-elite offensive production to his repertoire, on top of what already made him great.
Leech was a dynamic offensive defenseman. It’s flashy and impressive and exciting, but just not as effective at the position at the end of the day. A modern day equivalent would be a guy like Evan Bouchard - he might win a Norris eventually, maybe even a couple because of his incredible scoring, but I’ll never consider him the best overall defenseman, unless he seriously changes the way he plays the game or adds facets that he doesn’t currently have. And I say that as an Oilers fan.