Well.
I have explained many times why I have one system, and why I consider Hachimon a Kekkei Genkai.
To be short:
All abilities powerful enough to drastically alter yourself or the way you fight are considered Kekkei Genkai.
Tell me:
How would a bug user be able to learn Hachimon?
First, I am pretty sure (as Shino does not move really fast) all bugs would get squished when he runs with super-speed =)
Both are no KG, so you can have both. Or? Oo
Wait, let's make a Sharingan / Hachimon / Chouji guy...
I am super quick, super big (Baika) and by the way I can blast you away as my Sharingan channels hachimon....
There is no time for that.
<---that's the one hand.
The other is simply that I try to make it that people CANNOT get any special ability and build up monster chars.
I do not like to have 2 systems that basically do the same.
It is hard to balance stuff as it is ... hence the KG categories.
I could limit you to 1. If you want another, you die and there is no further reset...
If you are for a "jutsu learning system" - that is a different story and would replace the current jutsus.
The current system already expects that every level you grow in proficiency, but if you want to train instead and not get auto-levelups on the specialty - =) great idea, hrhr