Interesting coincidence that the Nexus phones have always been affordable until the new Nexus 6 which will ship with Android 5.0
Is this because Google thinks they can charge a premium for an unlockable bootloader when other Android 5.0 devices will likely be much much harder to root?
I highly doubt that the very few people who root their phones are the focus of Google's business plan regarding smart phones.
Glad I've got the "unlockable" (for now) nexus 5!
Your bootloader should continue to be unlockable.
From an unlocked bootloader you can flash (or just boot without flashing) a custom recovery.
From recovery you can give yourself root (with a custom kernel if needed)