The manga is already complete but you think it should be longer and continued.

Angel densetsu.

ya

Cromartie high schoooool

None. But I can tell you some few ones that should be shorter.

Clock you apparently did not read angel densetsu.

Eyeshield 21. It should have been longer and have had a better ending.

Dragon Ball Saga. Akira Toriyama should make Dragon Ball GT on his own as a manga.

Black Cat.

Apparently, Yabuki was gonna continue it, but I don't see how he can if he keeps getting contracts from perverted writers whose only point of success is the artwork. (Read To Love Ru. You'll see what I mean. TLR itself could have done with a much better ending, and shortened by about a hundred chapters.)

I would also have liked to see more in the Rurouni Kenshin universe aside from badly-voiced OVAs.

Gurren Lagann. End of thread.

That's pretty rude for people that want to still post in the thread.

Jubeh@ no, I didn't.

Jai@ I don't share that opinion. I find Gurren Lagan all what I need (is perfect in the amount of episodes).

Now I remember one manga who I got shocked with the end, this is because the manga was canceled just in the beginning and the sad part, is that the manga has a great potential to become a next naruto (but more interesting).

Rest in Peace "Double Art", I will always miss you.

Awww fuck! I agree it was intresting although I kind of stopped reading after I learned it ended before it began.

No. It's perfect as it is. The only thing we could use is a spin-off about Lordgenome's time as a Spiral Knight or the pre-show adventures of Kittan and Sisters or Yoko and Company.

EDIT: Or a Double K anime or proper mango.

Yeah. True.
In the epilogue, you see Gimmy and Darry left a new series open for thought though.