You can try setting/adding debug.sf.nobootanimation = 1 to your build.prop

I anticipate a non-root solution for this. Accessibility apps need to read screen text too, and they don't need root.

It would be good to know how or why it aborted.

No, not a bad idea. I know how that zip works and it removes every other superuser program before installing itself. If you're rooted, you can try different superuser implementations, I only suggested that because that's my favourite (Open-source, plus does everything that other versions' paid options do.) There is probably nothing wrong with using exploits to root the phone; I just try to avoid them because they are, after all, malicious code.

Rooting will also disable OTA updates from your carrier too. Which again is a moot point since you are installing a custom ROM anyway. Also, some software may refuse to run if it detects a rooted device, but there are ways to hide that, as GiantTree said.

Also, if you are planning to install a recovery, you probably are planning to install a custom ROM too. That makes rooting your current firmware useless, since it will get overwritten by the new ROM.