Make it an official stated policy that you support unlocking and rooting.
There are millions of systems engineers like myself looking to get away from Samsung and the like. We want replaceable batteries (requiring a screwdriver at most). We want phones we know we can customize and secure. We want to know that if we invest in a new device, we'll be able to keep it up to date (ourselves, if necessary), and not rely (exclusively) on a small and busy team. When there's a bug with a compass, one of us can fix it and submit a pull request.
I agree wholeheartedly! I was a user of the original CyanogenMOD back at version 4.12 and various versions up to Lineage 14. It was always annoying, wondering what hardware device wasn't going to work *this* time, because manufacturers always feel they have to keep some bit of necessary tech a secret. Usually it was some touted, key feature of the device, like back in the day my MyTouch 4G Slide camera would only do high definition videos if the factory "Sense" framework was installed, which meant proprietary bits in the ROM had to be used.
Truth is, if your tech is that important, you should want it supported by custom ROMs. Like he said, you'll benefit from the work of people who program ROMs because they ENJOY doing it and WANT to do it. There's no better reason to do something in life, and you'll get a better quality product from people who enjoy producing it than you will from people who just do it as a J.O.B. Updates will hit a bigger audience faster, and YES, the devices will still be kept secure from malware by people like us who are systems administrators and systems engineers who not only understand computers but also how to keep them secure. Sometimes it's as easy as not using porn sites (especially not using porn sites for fota severs).
There are those who AVOID a device like this because of the lack of that type of support. It's like the manufacturers are afraid somebody's going to reverse engineer it or something. I bought the 9500 pro for the two way radio, but I can find no custom ROM that will support that bit of hardware. If I could have, I wouldn't be using your ROM that doesn't let me properly explore my own file system, and properly clean out files from deleted apps; I wouldn't have the Google spyware installed by default; I damned sure wouldn't have that Adups spyware insta...... Oh, maybe *THAT'S* why you don't support rooting... You'll lose the spyware returns.