You're aspiring to a difficult project.
Asking for end user input, and could end up with something along the lines of the Homer Car from the Simpsons.
A bit of everything to everyone.
A friend of mine once designed a rifle for a competitive military bid, and submitted 5 examples. His rifle was the runner up, if he'd followed his own instincts and put a detachable mag on, he'd probably have won.
Follow your instincts on this, and take everything you get from here with a grain of salt. Recall the "CGN Lower" thread of earlier in the year where everyone and their dog came up with their own design for the "art" and markings on the lower. Impossible to come to a real consensus, and those who don't get what they want will reject it out of hand and look for faults.
You already know what you want, otherwise, you wouldn't have brought the project here.
Build the rifle.
Build it well.
Test it hard.
Sell it.
It's merits will sell it, or not.
If it doesn't sell, then you're out a bunch of money, but you'll have a bunch of guns.
If it does sell, stand behind it, and fix any problems that crop up.
It'd be hard to outdo the AR type platform, recall, they have almost 50 years of de-bugging behind that platform now. Same with the FN, the AK, the M-14, etc.
None of those rifles were perfect when they were first issued. Even the FN's had problems with pierced primers and the 1 piece firing pin.
Be prepared for teething problems.
Good luck in your quest, and feel free to share your ideas/drawings with us, but be prepared for some users here who will never be satisfied no matter what you make, particularly if you don't use "THEIR" idea.
NavyShooter