I think there should be restrictions made on bloodlines(there are 2 parts to this suggestion)
I think that people should only be able to have a limited number of kekkei genkai(this can depend on the levels of the kekkei genkai) for example, it would be impossible to have rinnegan + byakugan, or Byakugan + sharingan, or EMS + Ice + bijuu. this is only fair, and helps prevent the rigging of charactors so they arn't overpowered.
second part:
I think there should be restrictions placed on the use of higher level kekkei genkai, for example EMS user's should only be able to use instant space/time jutsu like only a couple times, cause of the cheapness of the jutsu cause it allows you to avoid any technique. I also think there should be restrictions on like MS jutsu, like only be able to use amaterasu/tsukyomi like 3 times in a battle(even itachi could only use it liek this number of times) then susanoo like only twice in a battle.
I think that people should only be able to have a limited number of kekkei genkai(this can depend on the levels of the kekkei genkai) for example, it would be impossible to have rinnegan + byakugan, or Byakugan + sharingan, or EMS + Ice + bijuu. this is only fair, and helps prevent the rigging of charactors so they arn't overpowered.
second part:
I think there should be restrictions placed on the use of higher level kekkei genkai, for example EMS user's should only be able to use instant space/time jutsu like only a couple times, cause of the cheapness of the jutsu cause it allows you to avoid any technique. I also think there should be restrictions on like MS jutsu, like only be able to use amaterasu/tsukyomi like 3 times in a battle(even itachi could only use it liek this number of times) then susanoo like only twice in a battle.