When the Projectinator ranks draft-eligible players, there is no consideration as to what position a team might be in need of. It assumes that you'll be interested in drafting the best player available when it comes time to pick. However, in reality an NHL team might (for example) be desperately short of defensemen, and so focuses on that position when selecting playersignoring a forward to draft a somewhat lesser quality defensemen, for example.
On the whole, this does not seem like a sound strategy. For one, the needs of a team can change significantly over the span of a few seasons, which is how long you'll have to wait for your drafted players to reach their prime years. While waiting for your newly-drafted prospect to mature, you might sign a quality free agent blueliner or two, or maybe your star forwards will decline suddenly, leaving the forward unit a bigger weakness than the defensive corps. There's a good deal of uncertainty in predicting the future of your team, and passing up a superior player based on your vision of the future is a risky proposition.
For another, it's unclear whether shoring up your weaknesses is a better approach than accentuating your existing strengths. There seems to be an assumption that if a team is weak in a particular area, it should make efforts to reduce that weakness, even at the cost of giving up some of its strength. There's no particular reason why this should be true; adding more offense to an offensively-gifted team makes that team even more powerful in the goal-scoring department. Why is that better than making it better in the goal-prevention department? It's goal differential that ultimately matters; if you score more than your opponent, you win. You can do that either by scoring many goals, or allowing few goals. They both work.
For yet another, but related to the above, is that you always have another roster spot available. You might have two great forward lines, but that leaves another six positions available for another quality forward. No team is ever so stacked in its 18 positions that it can't find ice time for another good skater. Even the 1976-77 Montreal Canadiens used players like Pierre Bouchard, Rick Chartraw, Murray Wilson and Bill Nyrop. No offense to those fine players, of course, but they were hardly irreplaceable.