I would prefer a team does a scorched Earth rebuild rather than rebuild a team that finishes 9th in the conference one year, 10th the next year, 11th the next year, 9th the next year, and so on.
Trying to rebuild while at the same time trying to be competitive simply lands a team in purgatory.
With some exceptions (the Bruins, for example), the pathway to becoming a serious contender and eventual Stanley Cup winner is usually a direct result of finishing in last-place (or close to it) for several years. This is how you manage to get franchise-shifting players on your roster.
Penguins, Blackhawks, Lightning, and Capitals. Look up those team's rosters and then look at many of their key players. Then look up what draft position those players were picked.
Even arguably the Kings most important piece (Doughty) was picked 2nd-overall.
If we want to discuss the Senators, then if anything they didn't scorch the Earth enough. Because if they could have successfully tanked for one more season, then that would have gotten them one of Power/Beniers/McTavish (all of whom would look very good in a Senators jersey).