How did you reach the conclusion that is not four years ahead from l2jserver?
Did you see any l2jserver problems like monsters teleporting on other ground layers? Corpses not decaying? Airships stuck?
Currently, eight years after the release of HighFive, l2jserver still misses things that people expect to work after all this time.
Pailaka Injured Dragon (Zoey, if you see this, I still wait for your version),
Nevit system, made by Janiko and later with listeners by me, as requested from inner team (Zoey again, still wait for your version),
with knownlists and several core systems been a mess, mostly because of misinterpreted OFF files information,
or just incomplete, abandoned, massive reworks. The list can go on, literally, for pages.
I also have broken things after trying to make something better, but never abandoned it until it was fixed.
If this did not cover you, use my forum to ask more questions.