While I agree that the 10 point system may not be the best, it is what is currently being used, so we have to go by that.
I think that in modern mma, too much emphasis is put on the standup game. Guys get stood up from the ground if they aren't active, but nobody ever gets put on the ground if they are just circling on their feet. Takedowns are an important part of the game, and it is a way to score points, and it is also inherently what mixed martial arts is. If a guy is a great wrestler, and a average puncher, and a average BJJ guy, he is going to use his skills to try and win a fight. Those skills are going to be taking guys down, and roughing them up on the ground. Why should he be forced to try and trade punches with a guy whose strength is punching? Should that guy be forced to go to the ground and out-wrestle the other guy?
The way I see it, there are different areas of a mma fight, punching, clinch game, takedowns, ground game, damage shots (kick or punch), kicks, and so on. Not every fight showcases all of these, but most will have a little of some, and lots of others. When a fight goes to a decision, ultimately, I think the score should show who has won the most areas, because obviously no one was good enough to end the fight in one of those areas.
In this fight, I thought Bisping won more areas than Wandy. He was better in the stand-up, and he scored numerous takedowns, and he also (for the most part) shut down what Wandy's approach is (going nuts on his feet and looking for KO's), and made his opponent fight his fight.
BTW, I'm pretty sure takedown defense is part of the scoring.