A new coach would essentially be process of elimination. A new coach would eliminate for certainty that coaching is a main issue. If the players cannot perform under a new coach then we probably can't have significant success with the group of players as it is. The fault would fall on the players for not performing but also on JB for not being able to put together a group that can have success.
In which case a soft rebuild may be the best course of action. We have enough young talent to do so. Keep the young players like Petey/Demko/Hughes/Hog/Pod/Rathbone and maybe Boeser. Initially trade away the veterans like Horvat/Miller/Pearson maybe Boeser in order to net a solid return of high picks, good prospects and/or a young NHLer with promise. Look to trade other vets afterwards(Poolman/Hamonic//Myers?/etc maybe Garland/OEL too but they might be worth sticking around). Have a 2 year phase of garnering young talent and begin to build the roster off what you'd have at that point.
We'd definite be absolute crap without Horvat and Miller for a time but you'd look to add solid veterans after the soft-rebuild phase to fill those holes and you'd have young talent knocking on the door at that point as well. These next two drafts present a good opportunity to do it if this team proves incapable as a whole, especially if we may draft top 10 again. Without Miller/Horvat we'd probably be looking at top 5.
Like I said though that should be the last option when we've exhausted all others. Hopefully it does not get to that point but I would want us to be prepared if it does.