Originally Posted by
MoanaLisa
Very successful games always become more conservative about their designs. The most obvious reason is that "wild" design is a risk and very often can kill a game outright. Blizzard's development team is full of theory crafters, engineers and the like that are by their nature not likely to be on the bleeding edge of creativity. Risk-averse is the watchword and it's very easy to see.
The one thing that rings true about the topic is that Blizzard used to project and protect a reputation for continuous improvement and iteration. Once the switch was made to expansion-specific systems that only exist in the game for a relatively short while—a single expansion usually—the days of improvement through sustained iteration ended. They release a lot of half-baked systems based on interesting ideas, perhaps improve them once for the last patch of an expansion and move on to the next temporary system.
So of course the quality and overall polish is reduced.