If your philosophy is to only "go for it" when you have no deficiencies and deep at all positions, you might find that you will be waiting for a long time.
There are no rules that say you can't grow while still pushing for playoff success. Zuccarello is not blocking any deserving youngsters from playing significant minutes in the NHL.
The Wild are contenders. I have them as a top 3 team in the central and one of the top 4-5 teams in the West, overall. No reason to take the foot off the pedal at all. They will go as far as MAF and their special teams will take them. Zuccarello only helps.