I actually REALLY love the longer anime opening sequences, especially in long running anime series. They're usually really well done and I constantly find myself arguing over which one is best; I even have a full playlist of anime openings that I really like....
Plus, like I mentioned before, it's even better to me in a long running series; take for instance me:
Just recently, I decided to finally start watching Naruto Shippuden (also known as my current FAVORITE overrated anime series) and every time I watch through enough episodes to get to the next opening song, if feels like an accomplishment and it also hypes me up for the coming events in the next string of episodes.
I don't really think that long opening sequences are the real problem with anime; the big problem, to me, is more so focused in the ending sequences that almost NEVER fit the show they are set to. They're JUST as long, or maybe longer even, as the opening sequences and, yes, I know, credits HAVE TO be shown, but I really wish that, in THIS instance, Japan WOULD take a page from America's book and just roll the credits along the bottom of the screen during the end of the show (maybe add some cute, OBVIOUSLY ENDING, music, lightly, in the background for effect). There'd still be more time for story, the credits would be shown and EVERYONE (save for maybe the animators and budget people... >,> ) would be happy