[Moto X Q&A] KidJoe:
I don't proclaim to know the ins and outs of all things android, but I do know this.. Just because a phone has android 4.4.4 doesn't mean its the same 4.4.4 with the same exact flaws and vulnerabilities, susceptible to the same exact root processes. Its why an exploit to root one phone, often doesn't work to root another.

In the case of the Moto X with a locked bootloader, JCASE has come out with many processes exploiting vulnerabilities for Android and the Apps on the Moto X to not only root it, but disable its write protection. As new OTA's have patched an exploit, he came out with other ways.

Starting wth 4.4.2, the vulnerability in the bootoader to disable write protection has been patched.

Jcase's Sunshine tool works on the X with 4.4.3 and lower, and only SOME with 4.4.4. It needs temp root first, etc. For whatever reason, we don't have a way to even temp root the 2013 X on 4.4.4 enough to allow Sunshine to do its work. And despite being asked many times, Jcase pretty much said in the Sunshine discussion threads that v3.0 wont have Moto X 4.4.4 support (unless he changed his mind and I missed it). Yet sunshine and its root processes, etc work on other phones (HTC) with 4.4.4.

But back to the thread you link...

On the X, due to its security measures, with a locked bootloader, you can only flash the Moto signed ROM for your phone. Nothing else. Because of this, you can't flash a custom recovery. To flash items, we use mFastboot and RSDLite. They need the img files, or bin files. If we make our own, they wont be signed, so they wont flash to a phone with a locked bootloader. And you can't package them into a flashable ZIP because stock recovery looks for the Moto digital signature (which we don't have and can't fake), and you can't install TWRP/CWM/Philz/etc to flash that way. So if you manage to pull the JB kernel out of the Moto SBF file, you wont be able to flash it.

Due to write protection on the 2013 X, any changes made to /System and a few other places, will be lost at power off/on. In other words, if you do manage to flash it (or push via adb), it wont stick due to write protection.

We've seen people try and manipulate their phone by trying to DOWNGRADE their ROM. Well, this doesn't work either. GPT.BIN (partition table), and Motoboot.img (bootloader, TZ, and a few other things) get in the way. Even on an X with an Unlocked bootloader, you can't downgrade these parts. Enough who attempted this have ended up bricking their phone immediately, or with later taking an OTA. Sure you can try to flash just system.img, and while that has less risk for bricking, people who have tried this were still not able to use the older Root Exploits (that worked if you hadn't upgraded already). People have tried flashing everything but GPT.BIN and MotoBoot.img. Again, it didn't help with rooting. Not to mention with a missmatched system.img or other parts, features on the phone may not always work properly (going Settings -> Security comes to mind), and you are at risk of bricking should you take an OTA update.

Since that process exploits a vulnerability, and its out there (so the vulnerability is in the public), I'm sure if it worked or was possible, JCASE, Beaups, or others would have put something together.

Now, back on topic of the XT1053... it has an Unlockable bootloader. Unlocking the bootloader disables write protection, and allows you to flash non-moto stuff. So unlocking the bootloader, flashing TWRP, reboot bootloader, enter TWRP and root, is quick, easy, effective, and doesn't rely on vulnerabilities on the phone to be exploited so patches/updates haven't got in the way. Plus you don't have to wait for someone to find them and create a repeatable process.