The defense will be fine for the foreseeable future. Sure it would be nice to have a #1D but Klefbom and Nurse are anchoring two top 4 pairings very nicely and are entering their primes. We have solid, cheap depth that will be plug and play each year in defense, and you keep the ones that exceed expectations and sell high on the others for picks or other depth pieces.
This team REALLY needs another gamebreaker in the top 6. Neal is a good sniper but he's not exactly a gamebreaker, more an opportunist and he's got a few years left in the tank. Need someone fast and reasonably young that has the skill to draw in defenders like McDrai do.
If it's not Hall it's got to be someone around his level. He's probably the best option they have (ex: actually available!) and if he does want to come back he will likely sign for under 10 million AAV. We hear the comparisons to Tavares but IMO Tavares has maybe a little more cache than Hall does (not saying he is better than Hall).