If you model this change mathematically, overall finishes of top shooters are affected only slightly, but enough to make differences in who wins. While a simple model predicts this to be somewhat linear across all shooters, if you factor in skills (calling shots for example) lower level shooters will see their final scores increase more because they will focus on making hits and therefore the matches will be pretty slow. Watching someone shoot an 18 second stage in 40 seconds in annoying and can increase the time it takes to complete a match.
I shoot a lot of IDPA. IMHO, the rule changes just lead to endless range lawyering and make it hard to have a consistent match. Different SOs call stages at monthly club matches AND sanctioned matches differently so in many cases, everyone is shooting a different match. To me, this makes it less of a sport.