School Rumble has a lot going for it. A potentially deep and engrossing storyline, humorous setting, interesting and varied cast, and it managed to last a surprising 22 volumes, so it has to be pure awesome, right? Not so.
To its credit, School Rumble has some of the most interesting characters I've ever read, and the Tenma/Harima premise hooked me from the start. But after 10 volumes or so, the constantly recycled plot devices, jokes, and "better luck next time" moments became merely irritating thanks to the utter lack of plot development.
Furthermore, the cast of SR is so unmanageably large that it's hard not to imagine readers completely forgetting about many of the secondary characters. I have nothing against a lot of characters, but this series juggled them poorly, introducing yet more forgettable characters even when there were still too many unresolved subplots to tie up.
Last of all, the random humor and unexpected (but sloooow) plot twists definitely drove this series' appeal for a while, but I found it unnecessary and frankly unwise to keep it up even when the plot was finally winding down. Because of the frequent "twists", some promising relationships are suddenly sidelined, and the involved characters are forced into being supportive friends without any rationale whatsoever.
Case in point: Yakumo, one of the most endearing characters in the series with a serious storyline to boot, finally works up the resolve to admit her admiration and love for Harima, and goes unheard because Harima's personality does not allow him to deviate from his feelings for Tenma. But see, that's not what I have a problem with - it's just that after all that character development, she is never really mentioned again. The timeskip ending is no excuse; time healed her wounds? Horses***. No explanation, no conclusion written for Yakumo. Just a loose end for a major character. Unacceptable.
Finally, art is above average at best, with some very nicely done panels for important chapters, but all too often it is seemingly rushed and barely serviceable at times.
Honestly, 30% of the series just felt like the author was attempting to drag out the series as long as possible to maintain sales. That said, I can understand why the anime was so popular, since it HAD to end at some point.