My idea of a great phone will be the following: Make a closed device for the masses, so they can mess thing up just because they try stuff, and offer the possibility to switch this device into a developer/hacker device. You pay a fee and they give you source and whatever else you need to make this an enjoyable device for developers too. This way you protect the dumb, and give satisfaction to the tech maniacs.
HTC is the only company who have this option for the customers. Get a HTC and you get it locked, running an Android branded by HTC. If you want to take it to the next level visit http://www.htcdev.com/ which is an official website by HTC and unlock your device to have access and mutate this device after your own will. Too bad MS is never going to do this for any device (checked the website for dev unlocking for my 8s and guess what, it's not there, because IT WOULD BE USELESS since MS have not opened any sources).