But quite often the X-Factor in these types is you never know which player will turn up on the day. The one with the mercurial genius or the one that goes completely missing with two touches to their name. They generally also have less to offer in a forward defensive role. All cream and no cake.
Sure its great to have a surprise package but you can't build a reliance on them to do a job for 4 quarters and more often than not they just end up as another flash in the plan. If you run the stats I think you will find that more of these types fail than succeed. In today's game, if you run a weak link for more than a quarter, opposition teams will expose you big time.