The reason clans worked in three brackets back in the day was because there was competition in each bracket, because of the number of clans competing, each bracket had standards and each bracket stuck to those in order to be considered LPC, MPC or HPC. If you did not comply with the standards of defense and combat levels of each bracket, then you were not given fights and you were essentailly black listed until your clan dwindled away into a slump and eventually death. I believe today there are enough clans to make an HPC scene, a MPC scene and an LPC scene. There is no reason why we cannot have ALL three. If the proper standards are set for each, then based on the spirit of competition, each clan will abide by the norms. if you want to be an LPC and base your clan off def levels of 1-5 then fine. If you recruit members that are 90 combat and 1-5 defense then fine. NOT a single clan in your bracket will prep you in CW with a 90cb cap. If you go to the wild with your big level 80's in 1-5 def range, thats fine also. Guess what? you wont find many fights deep enough for those high levels to make a difference for your clan against other LPC's.
I do not think there is anything wrong with basing your clan off combat ranges such as 60-75. Nor do i think there is anything wrong with basing your clan off 1-5 defense. Hypothetically, two clans in the same bracket can still COMPETE in a fair playing field with different requirements such as 1-5 def or 60-75 cb. The deciding factor will be how the rank team in each clan strategizes there recruiting and member base. Recruit all the 90s u want in you 1-5 def reqs and risk being marginalized because your clans cb averages are all over the place OR base your clan on 60-75 and risk less recruiting potential and maybe a smaller pull and less raw power in your average member.