It is not hard to find other examples of key young players whose negotiations took until mid-September and even later. Pietrangelo is one of the few really good comps for Seider as a two-way D who had early production success but never built on that to get to another level. He signed his first post-ELC contract in mid-September, his seven-year deal at just over 10 per cent of total Cap at that time is probably where Seider will end up if he signs long-term. Connor and Pettersson took even longer, until late September/early October, one getting a bridge deal, the other a seven-year deal. The short-term deal for the Canucks eventually worked out better for them than the long-term deal the Jets signed with Connor. Both players struggled a bit the following season but in the long run it didn't matter. Nylander's post-ELC deal took until the Dec. 1 deadline, didn't really matter at all that season or in the long run for the player or a particularly poorly managed team.
Nor is it hard to understand why negotiations are taking longer than panicky fans would like. If we're being real here about resumes/expectations, Raymond has just one season of top-end production while also elevating his two-way play; Seider's production has declined and Detroit may not project him going forward as a PP1 guy scoring 50-plus points. But in both cases, particularly Seider, their value is more than the points they produce and it's not unreasonable at all to think they both may have more offensive upside. So yeah, sides get entrenched, hard to find common ground, It shouldn't surprise anyone if the eventual common ground for at least one of them is less than the max years.
If it appears SY may be playing hardball here, it's for good reason. Seider/Raymond could turn out to be the best and highest-paid players of anyone SY has drafted to date. Signing them to fair contracts, whether it's three, five or eight-year deals, would set everything up Cap-wise for years to come. Overpaying them now, just to get it done, could lead to more overpays down the road as players/agents judge their value relative to the guys being overpaid, and less room to add whatever's missing. Any short-term price the Wings may have to pay now for their absence or a slow start is worth it if makes things easier when seasons will matter more than just trying to get a WC berth.
Bottom line, it does not matter at all how long this takes. What matters is where it ends up in terms of dollars and years, not when.