I remember watching McCann in a pre-season friendly at Eastleigh. He was so comically poor I doubt he would have made The Spitfires bench that day.
I seem to recall his signing being the start of Strachan's demise but time might be affecting my memory on that point.
Very subjective of course but Les has also signed the likes of Forren, Juanmi, Gardos, Lee and Mayuka. Plenty of misses to go with the hits. But you are right, he's not the messiah. Nor is he useless.