Definitely an interesting topic. I'm on my first run through LoS right now and I'm only at chapter 3 at the moment so I can only discuss the game based on what I've seen so far.
I was the biggest defender of LoS before it came out, especially when people were saying "It doesn't look/feel/etc like Castlevania." The videos I watched (mainly of the first levels) looked pretty well in line to me. But as I started playing it, I began to see what they were talking about.
Now don't get me wrong, I'm enjoying the game on its own merits thus far, but it's big flaw is simply this: At no point does the game allow me to forget that what I'm playing is a pastiche of other popular games. The comparisons to God Of War, SotC, and others are fair comparisons but only because the game itself invites them. The controls are exactly like God Of War's (so much so that I even find myself instinctively doing that Square, Square, Triangle Plume Of Promethius BnB combo, or trying to anyway), the whip looks just like the Blades Of Chaos, the quicktime events, the climbing, etc. ALL screams "God of War." It does TOO GOOD a job at emulating games that were obviously used as templates.
And maybe we should have expected this, seeing as how Castlevania has relied on other games to set the tone since, well, probably near the beginning. Castlevania and Simon's Quest are the only games in the series that aren't based on some other game, and who knows, maybe they were too. Castlevania 64 might be another one, although it may have been patterned after LoZ. I don't know. But it's pretty clear that most of the more recent CV games have been based on something else, so why should LoS be any different? I guess for my purposes, I don't mind that they base parts of the game on other games, but at least try to do a better job of covering up the source material. For all their flaws, the Castleroids did this pretty well. I mean, you could always tell they were kind of based on Metroid, but they never put a character shooting a cannon and using a Maru Mari style move or anything like that.
As a fan of the classic CV games (Simon's QUest is the reason I started playing games altogether), I feel like they were generally better designed than anything we've gotten since although AoS is a contender for sure. I've learned to like the Castleroid games over the years and Symphony ranks up there as one of my favorites, but I don't know that I would call LoS a "return to the series' roots" or anything of the sort. It's a good game to be sure, but if anything it severed the series' roots.
But with all that said, Castlevania needed an update. It's been a middling series at best for the past 10-15 years, one that people pay lip service to when they want to show their "game cred." And while any update would have likely been a drastic one, I'm not sure they went in the right direction with LoS quite yet. I've still got quite a bit of the game to play through, and I'm liking what I've played so far (minus the Titan battles), so time will tell.