Author price changes, nonono, easiest way to kill the marketplace. Won't ever happen tho thankfully
Discounts instead of bundles.. I think the idea has merit, but there are two possible drawbacks I could see.
1)Envato takes a large cut of every sale across the market, cutting prices by 25% or more across the board would be a fair amount of revenue for them if the sales didn't rise enough. Not saying it wouldn't pay off (I think it would) but Envato would be risking a significant amount so might not be keen to jump into something like this.
2)If decreases became commonplace (say 4 or 5 per year) some buyers might hold of buying until the price decrease.. no idea how many might do this, but worth consideration.