Dell was ultimately suspended for 3 games by the NHL's Department of Player Safety, but the damage is done and, in this case, the punishment does not fit the crime. Any time a hit like this occurs, or a goalie decides to leave the net to play the puck, the debate starts up again.. should goaltenders be fair game for players?
There are arguments for it. Players have to tip-toe behind the net when forechecking to avoid taking a penalty for running into the goalie and sometimes goalies simply get more involved in the play than they should. Being fair game outside the crease would certainly make them think twice about taking liberties on players, or even asserting themselves and taking risks when they probably shouldn't.
The problem, however, is that goalie equipment is made to stop pucks, not protect against physical play. There is next to no padding on the backside of goalie equipment, so any hit that results in an impact to the back is going to do damage. Goalie masks also come off very easily in physical situations, which puts them at a much higher risk of suffering a head injury. Altering the masks to protect against hits isn't the answer either, because they are built specifically to deflect high speed shots and a change in shape would affect their ability to do so safely.
Lastly, if you've ever skated in goalie equipment you know there's not much mobility while skating upright. Goalies can't dodge, or really brace themselves like a player can. It's simply not a fair fight.
Dell has been penalized in the past for this type of play and, while I believe this kind of hit from a goalie is a cheap shot, I don't believe that making goalies fair game outside the crease is the right move, unless you want to see a goalie carted off the ice on a stretcher every week. There simply isn't enough depth at the position in the NHL to allow it. Just my two cents.