Like anything that is handicapped it will always be open to the term 'bandits' once you see a player/horse win an event where they would normally be nowhere near winning it under differing circumstances. I know some golfers who would struggle to play in the normal weekly comps off a 14-18 handicap but come the big cup 3/4 handicapped cup comps seem to play to a sub +10 handicapped golfer, win, then say they don't know where that came from... Equally, and I see this ever year in my local snooker leagues, some players would struggle off scratch in the league but enter the handicapped events and make semi's & finals nearly every year, stating that they just got lucky...
In my mind the handicapped system for horses is just a way of giving the lesser horses a chance of winning bigger races than they could actually achieve at their current standard, it's just finding that one that seems too good to be true in that race that it's got 'Bandit' written all over it...!!
Now, if you call that 'Open to improvement' or not, it's still a horse/player winning something that they couldn't do before, so that has to be an improvement in the end hasn't it...??