It is not the manufacturer who is the problem with locking down the bootloaders. It is the carriers that are requiring it. Motorola wants to sell the phone, AT&T and VZW say well you have to lockdown the bootloader if you want to use it on our network. So Motorola says alright. Thats why they will offer a Developer Edition, because if you buy the phone outright at full price, AT&T and VZW are unable to control it.
But on the bright side, the T-Mobile version will not be locked down per Motorola as far as we know. So there may be a chance to find a factory restore image for T-Mobile and push it to the AT&T model and resolve this issue.
I currently am using an LGOG from AT&T and while I was able to unlock it, there were alot of kernel issues at first with the phone due to LG. But we were able to flash the Nexus 4 factory restore image via the LG software and basically have an Nexus 4 and be able to use any of their roms. Just wait for it to get popular and get some Devs behind the phone.