Exactly Hayabusa, Your techniques even my own would still be classed within the CLAN ruling that is being passed because of the fact they are "?" and require our Clan's abilities to even use. So even when new players appear and see we have "?" ranked techniques it would be because of us using our clan's abilities or bloodlines.
Enjin: Increasing the effects of the other jutsus have would mean increasing the "?" rank as well. The ranks are set to show the progress of how effects grow to their final form. "?" Rank is different as again nobody knows what or how the technique really works besides the clan members so that would mean yeah they'll have a bit of an edge cause again we don't know the max effects a clan technique can really do.
like Choijo's clan, they could have the effects of, Increase/Decrease "Said" Attribute, x1.?? to DMG/Melee, STR Binds +/- by turns, Food Items +"Effect" after usage, etc.
Where if someone that has no clan, would not know that or be able to even come up with ways like that. At the same time it makes techniques focused on our said clan to rather we want the clan to become ours or not later down the line.