That one year is pretty much the exception.
Outside of that year, moving forward Leetch was pretty much a 10-15 goal, 50-55 point defenseman when healthy, he wasn't getting the the all-star votes anymore and he really wasn't consistently close to being one of the top candidates for the Norris either.
Yes those were not great teams, but Leetch also wasn't quite a great player on those teams either. At least not enough to really elevate them.
There is a distinct drop in his game at that point, and not just offensively. His defensive game really regressed as well. Granted some of that is the team, but there's no real getting around it --- beloved figure as he was.
His career, for whatever combination of reasons, really started to downturn quite a bit earlier than one would've expected.