It would be difficult to present the Holy Warrior without a pantheon. The skills, spells, titles, code of honor, and special abilities of the Holy Warrior are all specific to the deity. Sure, it would have been more economical to leave out the specifics. To just give one example, and leave the rest to the DM: add two skills, swap out X spells per level, and so on. But personally, I kind of feel cheated when that's done. It's a half-done job, like the Urban Ranger from Masters of the Wild. I'd much rather see a fully statted class.
It's like the Speciality Priests from 2E. How can you present a generic specialty priest class? You can, kind of, but it's probably better done the long way.
There's a good deal of crunch in the book, I might add. There are a lot of quality prestige classes in it, as well, that are specific to deities but not to clerics or holy characters. These are also very easily adaptable to any campaign.
If you just want a more customizable Paladin, I'd recommend Book of Hallowed Might, by Monte Cook.