Update 1.2 to Tales of Zestiria added a change that checks the file-size of the intro, and prevents it playing if it detects it has been replaced, thus #748240 doesn't work anymore. The old one will STILL play in-game at the point where it is triggered, just not on Title screen.
Helpfully DragonScy over at Reddit provided a solution for us;
Western version of Tales of Zestiria removed lyrics from the intro movie. Use this to get those back to the Steam version of Zestiria.
Instructions as follows;
-Open the game folder of your copy of Tales of Zestiria (Steam, PC), open directory RAW/MOVIE, drop this file in there.
-Find and rename AM_TOZ_OP_001.bk2
-Rename New_AM_TOZ_OP_001.bk2 to AM_TOZ_OP_001.bk2
Now, once the intro starts, it will include the lyrics instead of the guitar solo. This version will play even on the Title screen.
You can watch this file stand-alone too, but you need RadTools.
Now, is someone out there up for a task of creating a subtitled version of this file that can be switched in instead? (Granted, the check introduced in Tales of Zestiria patch 1.2 makes this a tad more difficult I suppose...)
A translated version of the intro movie can be found here.
If you want to do this manually, here is DragonScy's guide; (as quoted from Reddit)
Hey all! In the most recent patch (1.2, with all the bug fixes) they seem to have blocked the original japanese opening fix found at launch. There is a workaround though, but it takes a bit of effort.
The game is (apparently) checking for file size, so the easiest way to get around is change the file size. Using a bk2 file editor (like RAD Video Tools) you can add the audio and work around it. I used RAD, so this is an explanation with that software. Open RAD Tools and select AM_TOZ_OP_001, click "mix in sound", and select "AM_TOZ_OP_001_JP" from wherever you saved it before. Wait a few min, and you'll have another file that works!