The problem for finding a Seider partner is that his partner gets exposed to the same pressure Seider faces. Toughest QofC of any defenseman in the league, a No. 1 pair that starts in its d-zone more than any other No. 1 pair in the league, and unless playing with Larkin-Raymond a pair that gets what might be the league's least capable forwards of helping them defend in their own zone and move the puck out. It's a recipe for almost any Seider partner to be exposed and limits Seider's ability to contribute offensively.
Maatta would be exposed too. He's learned to be very crafty and efficient to compensate for his lack of strength and only average skating, but last year he had more give-aways than Chiarot despite playing five fewer games and almost four minutes per game less TOI vs. lesser competition. Neither is that challenging Seider environment a good idea for a D that is essentially a rookie. Even Seider had an easier NHL introduction his rookie year, with about 50/50 zone usage and an experienced pair behind him anchored by Hronek. As Seider has established himself, teams have figured out one of the keys to beating Detroit is to swarm him on the forecheck, forcing him to move the puck to a partner inevitably less capable than he is, or to forwards that if not named Larkin/Raymond are likely to screw up or just be invisible. It means Seider and his partner spend most of their shifts in their own zone,, often looking for a shift change when the puck is finally moved up-ice.
A whole bunch of things have to improve and will improve to make life easier for Seider and Partner X. Probably the most important is finding a good second pair that can take some of the heat off. Edvinsson has a great chance to be part of that second pair because he is so good defensively. Give him a couple years to establish himself and become more confident with the puck and the Wings will have the needed two-way anchors of a very good top four, almost regardless of who their partners are or what they bring. They can be pure D-zone capable vets getting 15-20 points a year or offensive wizards like ASP. The forward group is going to improve as solid two-way guys like Kasper, Danielson, Mazur, MBN become regulars. But for now, Seider's partner is going to be somewhat of a sacrificial lamb and Chiarot is the best candidate for that role.