Their roster is very mid. I think they are right where they should be. That is, battling it out late in the season for one of the last playoff spots, regardless of the various streaks and levels of variance to get them to this point.
They'll have prospects come in and gradually replace the free agents the next few seasons, you can see who is expiring from the cap table here. I would expect most players with "UFA" in the next three years to not be re-signed and replaced from within, which will basically be most of the current roster over the course of three off-seasons.
Detroit Red Wings salary cap, contracts, roster, draft picks, salary, cap space, stats, salary cap projections, and daily cap tracking
www.capfriendly.com
Still around will be:
Mortiz Seider (re-signed, maybe 7 or 8 year extension)
Lucas Raymond (re-signed, not sure if you go long there or more like a 4-year bridge to take him a year before UFA)
Jonatan Berggren (recently graduated prospect)
Joe Veleno (RFA, probably re-signed in a way to bump up against UFA years or maybe go slightly into them)
Dylan Larkin (signed long)
Alex DeBrincat (signed 3 more years)
Andrew Copp (signed 3 more years)
J.T. Compher (signed 4 more years)
Michael Rasmussen (signed 4 more years)
and then of course, whichever prospects emerge from the existing pool
The question becomes, will the prospects they graduate be better than the mid-level free agents they replace or be more or less around the same level?