I just added both his ost theme and the theme you hear when you fight him ingame. There are a few videos here, just look up. Old king allant theme extended.
Making the organ less prominent changes the entire mood of the fight and makes the OST too much like Dark Souls and Bloodborne. Demon's Souls had a very unique OST, so people were sad to see that get butchered hard to appeal to a larger audience.
Tbh although i prefer the original, the part from 0.00 to 2.02 is really good, but the rest of the song just completely misses the point of the fight. Sounds like a phase 2 kind of thing, which Allant do not have and so it really seems out of place