If people copy Dark Souls, I can't say I'm surprised, but I don't see that as a bad thing. As Yahtzee points out, we've had our era of Doom clones, GTA clones, and I'd raise him with WoW clones, and more recently, DotA clones. Remember when everyone was trying to copy WoW? Remember how everything seems to be a MOBA now? I don't see either of that as bad in itself, because by the end of it, MMOs that came out after WoW are still around, and there's been some MOBAs that have broken the DotA mold (e.g. Smite and Heroes of the Storm).
So yeah? Dark Souls clones? I'm fine with that. Going by history, by the time the phase is over, we'll be left with some good products while the chaff will be forgotten.
Caveat in that I haven't played DS or LotF, so feel free to take everything I said with a grain of salt.