Lament of Innocence was a bit of a blast, OST nails atmosphere and the Forbidden One's den is down-right chilling. For the most part the game is well designed but I feel that a level-up mechanic was lost (probably due to that stat view), the only real set-back of this game was the backtracking for the relics that all revolved around getting a key, going to a door that you may have remembered, getting a relic and a key, rinse and repeat. Graphically it's fine, but could have used more variety in lighting to make areas more distinguishable and could have used more of those well-though-out puzzle and platforming sections. The AoS easter egg is also fun and the Jewel Crusher is a nice way to utilize other-wise useless shop fodder.
Curse of Darkness is technically very impressive, plenty of weapons, crafting, and mechanics to go around. The Innocent Devil system is quite amazing but a little on the grindy side since you'll only scratch 1/4th of it's content alone on a first playthrough (not to mention how ridiculious it can get with invested time). Levels are HUGE, a little too big at times, not helped by the fact that Hector suffers from the same condition SNES Richter has where the movement speed is pretty slow but is distracting because the animation is playing too fast resulting in a skating look about it. Weapons have depth... but It's more Dynasty warriors where your combo adds one attack and one finisher per upgrade, but the variety of weapons do make up for it (The Power Glove, It's so BAD!), Playing as Trevor is pretty awesome as his dagger crash is still really cool so see in action. The biggest QoL changes would be cutting the Innocent Devil grind down a bit, New Game + into Crazy mode, and that damn movement speed.
I would recommend these both to be played on an emulator (just buy and back-up the discs), the resolution bump and widescreen are enough enhancement and maybe when PCSX2 supports texture replacement, maybe we can see some Hi-Res textures. This does bring the question, are they even worth your time? Yes. They are flawed and show a bit of age, but even non-Castlevania fans seem to enjoy these ones, In time maybe they can get those needed QoL improvements with Rom hacking in time, after-all we are living in a time of Widescreen Snes and a native PC port of Mario 64.