Neji makes this a kekkei genkai.
I don't think the eight gate manipulation is a kekkei genkai, but I think Neji knows this.
Also, for balance purposes, it's about right.
Similar? Sure in power, but it isn't something you are born with.
Like Kakashi mentioned about Lee when he got to the 4th Gate "that is not something that can be done with training alone, he must be some kind of genius" ...
and a constant work, for *years* since being little is what you need, I say it is the same like being born with an extraordinary ability you have to train constantly alike.
When Kakashi said that, I think he was just complimenting Lee since Lee is a "dropout".
Being a genius doesn't mean one has kekkei genkai, but that they have talent.
Like Orochimaru or Minato.
I don't think they had kekkei genkai, but are considered geniuses.
Since the eight gates are so powerful and require years of training, You want to group this with a loose definition of kekkei genkai?
I'd rather see the eight gates done in a similar fashion as rasengan because it is something most people can train for.
Or this should be grouped with jutsus like puppets, shadow bind, chakra bugs, etc.
Unless those are being grouped along with kekkei genkai?