I have two ways of looking at this issue. On one hand, I don't really mind the 3-hour format. Although Bischoff himself stated that he regreted ever making Nitro a three-hour show since he felt it overexposed and burned out the talent, I don't feel it makes a whole lot of difference in the long run. When Raw was two hours a week and ran every week of the year except for Christmas, you were still watching over 200 hours of WWE television a year when you also count Smackdown on top of it. When you're already willing to watch THAT many hours of WWE television a year, is adding an extra hour on Monday nights really that much of a difference maker? Sure, you end up with a lot of filler, but you're gonna end up with filler on the show either way. Go back and watch every episode of Raw out of the years when it was only two hours, and write down all the matches that you end up seeing a dozen times or the number of segments that end up going nowhere in terms of developing any serious storylines. You'll still end up writing down quite a bit. When you've got that many hours of TV every year non-stop, it's practically unavoidable to end up with filler. (Then again, you could argue that as long as something serves a purpose on that week's show, it isn't necessarily filler even if it fails to impact the next week's show.)
On the other hand, I hate the three-hour format because three hours is just too long for a weekly show, especially since it's apparently hard enough for them to even keep it contained within three hours given that they usually run at least ten minutes in overtime. Plus, I really dislike the notion of a weekly show being as long as the monthly PPVs. And lastly, with Smackdown and one hour of Main Event (which is more or less considered the 'flagship show' of the Network) airing every week on top of Raw, an extra hour on Mondays isn't really necessary. Four hours of prime time television and one hour of Main Event on the Network should be more than enough time to develop any stories they want to tell.