I, personally, don't think stealth should've been mandatory. It should've been handled like you see in some RPGs. You can sneak past the enemies and avoid detection, and are rewarded for it, OR you can go all out and force yourself though, get penalized by taking damage, but nonetheless manage to defeat them regardless.
The earlier stealth part, the damage should be more drastic. But, later on in the game, the power should shift. Those guards should be downgraded to mere enemy status with weaker defenses and attack damage. There's no reason for them to be taking out Dracula so easily, and there's no reason such enemies should pose a threat where stealth is NEEDED. Stealth SHOULDN'T be NEEDED, but should just be an option.