The players the Isles lost hurt. The players that were added addressed key problem areas. Defense still remains a big question mark as does goaltending. Too many "ifs" to say they will contend for a playoff spot. But I also don't believe at this moment that they wont at least be in the mix as the deadline approaches. They could be anywhere from bottom 2-3 of the Metro to wildcard. That's why we play the games.
A "full rebuild" really is not something that makes a ton of sense. There is some real skill and talent on the ice. Barzal, Beauvillier, Pulock, Leddy, Lee, Bailey, Nelson and Eberle are all players that can figure into the next 5 seasons. Some are still young and developing. Others are established players. Add to that maturing players like Wahlstrom, Dobson and possibly others and you have the makings of a fine core.
Should the team falter this season, and be sellers at the deadline, then they can and should sell players who are not in the long term plans. My guess is Nelson, Flipulla and Lehner are the first to be offered at the deadline; although in Lehner, if he plays well, they may yet hold him. That group of 3 should garner 2nd-3rd rounders at minimum (a lot will depend how they play from the start of the season through the dealine of course). I believe you move Lee and Eberle for at minimum a first and a B level prospect at minimum. These are proven assets who can produce and if they are sure they are not coming back, then they need to get a high return.