Anybody who thinks a show (any show) should only go up to 64 episodes max is crazy. some of the best DBZ episodes were near the end.
Perhaps some of the best episodes of DBZ
were near the end. That doesn't mean I want to sit through 275 episodes of largely filler crap to find out, which is more or less what "Drag-On Ball Z" was. Like I said, the best and most consistent anime series I've ever seen have been in that 26-52 episode range. That gives writers time to develop a concept, introduce and develop characters and plotlines, maintain a steady pace, and then end on a satisfying note without having the series wear out its welcome. I've yet to see a series that goes beyond those 52 or so episodes that I would label as superlative. The longer a series tends to go beyond that basic "2 season" (more like "4 seasons" these days since 13 episodes is becoming the new standard) framework, the more you tend to see the writers straining to keep the series interesting, the more sequences that should be brief are stretched out to points where it's hard to care anymore.
Now, that observation may just be a result of incompetent writers in anime, because I've certainly seen excellent Western Live-Action and animated series that have run far past that mark, but I've yet to see an anime series that is still exciting to watch after that 52-episode mark. In general, keep it shorter and leave your audience wanting more, rather than making it several hundreds of episodes long and leaving your audience wondering if it'll ever end.