But in that case, you're penalising other players who have been on similar if not better runs, because he doesn't have a history built up prior to going on that run.
Ross Taylor had a run of 54*, 53, 217*, 129, 131
Jacques Kallis had multiple runs that would be similar to Taylor including a 91, 28, 51, 155, 100*, 59, 107*, 29, 186, 131
etcetera...
Which you've just confirmed by admitting that players who start on a blinder are given much more favorable rankings than people who have built a history, even if those with history have had much greater runs of performances.