It helps keep the pace of the original games alive. They're as iconic as the blocks in Mario games.
See, I'd disagree.
The question mark block has, much like the Mario series, not changed since its inception.
Castlevania candles, on the other hand, come in a variety of shapes and sizes, and, starting with Symphony of the Night, have been replaced in certain instances by non-candle objects, i.e. vases, pots, food, etc. Since Castlevania started becoming all about atmosphere, IGA's team would replaced candles with whatever enhanced the atmosphere, especially if candles didn't exactly make sense with the setup.
Hell, Simon's Quest even removed candles from huge parts of the game
Ultimately, my point is that seeing how Lords of Shadow used candles to enhance the parts of the game where they were appropriate, I don't see how shoehorning floating candles into nonsensical areas like the Classicvanias would be better.