Warrior Within is no Sands of Time. Most seem to agree. But this game does have some strong points.
The good: Level-design is still fantastic (as it was in SoT). Character animations are also still great. It's easy to see how this game influenced games like God of War (in terms of combat animations and mechanics). The environments and backgrounds in this game were beautiful.
The bad: Relentless, uninteresting fighting. Any fool can "button mash." That's just lazy game design. What was so brilliant about Sands of Time was that it forced you to rethink the environments; enemies in that game were a way of breaking up the action. Here, platforming puzzles are secondary to the (lame) fighting. Don't get me wrong, I enjoy hacking through enemies as much as the next guy, but it needs to be done well so that it doesn't become dull and repetitive.
More bad: I was also bothered greatly by having to backtrack a lot in this game. A well-designed game will provide natural "loops" in the progression through levels so that it never seems like you have to go straight back through a level. I spent way too much time travelling back over the same ground in this game for no good reason. Terrible design flaw.
Storyline: The storyline was lame. Not terrible, but just lame. Certain storyline and gameplay elements reminded me of the first Soul Reaver (on PS1), but I won't divulge what those are so as to avoid spoilers. The general progression of the plot, though, was stymied by the ridiculous backtracking (see above).
Overall, the game was worth a single play-through. As with Sands of Time, the difficulty was so-so. The game was a bit longer than it needed to be, mostly because of the senseless backtracking. It's more interesting as merely an example of the genre rather than an innovator.