The main problems seem to be:
-"We have taken the basic combat engine from Lords of Shadow and dropped it directly into the game." - no sign of understanding that 2.5D platformer combat is necessarily and beneficially different from 3D combat (as expected from a 3D dev); combat resembling LoS at all does not bode well for a 2.5D game since it would be unbelievably tedious compared to typical 2D platformer combat.
-"...with occasional shifts into full 3D gameplay" - this means you will be fighting bosses in 3D.
-Limited to one main weapon type per character instead of 10+ (still salvagable, but tends to kill replayability and beats down gameplay variation, making the gameplay more tedious)
-Experience being "spent" to unlock combos instead of causing level ups that increase stats (there probably are no "stats" judging from that comment, so more variation and depth out the window if that's the case)
-Only an extrapolation from what they didn't discuss and the 3D dev mindset, but probably no equipment, which loses a lot of flavor, weakens the "exploration" angle, and would be the final killer to any gameplay variation or depth)
-If there really are 4 different time periods, one for each of the 4 main characters they mention (2 still being unrevealed), it assures none of the 4 will have much depth. 2 wouldn't be much of an issue. Also, it assures what CV fans love to death: lots and lots of asset reuse.
Unfortunately, style analysis seems to be blotting out any rudimentary gameplay analysis with what was said in the article that could be happening at this time. I'm largely uninterested in the style discussion as long as the style vaguely resembles gothic horror, since style is not addictive, gameplay is.
Okay I see what you are getting at here but from what I am gathering these points are made out of concern and are really not problematic, the game was just debuted the other day so there is still a lot we dont know "occational shifts into 3d" does not mean we will be fighting only bosses from a 3d point of view it could mean during special combo or grabs the game shifts or certain areas are played in a 3d manner until there is concrete evidence of this it cannot be said that bosses are the only part inthe game where it is 3d.
As far as fighting is concerned taking the mechanics from los and moving them into a 3d manner doesnt take away from the gameplay given that games like mvc 3 which are technically 2.5d games managed to pull off extreme combos very well, all you do is eliminate the over all "next stage, fight" and make the game flow like a regular 2d side scroller and there you go though there are probably better examples of this.
If you really enjoy stats then yes this would be an issue but not every game has to rely on it. LOS did that very well and as far as equipment is concerned. Im gonna go ahead and say since they are taking a lot of elements from LOS then it may be safe to say that relics will be returning and replacing equipment cutting down on the need to purchase and sell items, you get what you need to survive with the relic system and plus offers the ability to return to older stages in the game to re explore areas you could not before which actually increases the exploration issue.
As far character depth I'm still not seeing an issue since the game was only debuted the other day, Trevor is already starting off with a nice story given it isnt really the same old "You killed my girl you gotta die" revenge plot and you are assuming that just because there are 4 time periods means the game will be short when however this game could be lengthy and actually address each character accordingly. The interview did state they would be addressing why Simon is more wilder and barbaric than Trevor, the same could be said for the other two characters.
So in all I am seeing some concerns not problems. The game has everything a Castlevania really needs, a whip wielding hero an art style which seems more familiar than what LOS provided, Dracula confirmed (none of that bait and switch crap we got from LOS) as the final boss, out door areas as well as the Castle being the final area multiple characters tho play as and from what I have seen a lot of returning enemies. The only difference from this and other CV games is that Dracula is in fact the Belmonts ancestor/father (for Trevor). If you look at it like this Castlevania didnt have much of a plot, it was a guy with a whip going into a Castle to kill Dracula to be brief. No character depth no love story no revenge just a sense of duty to go destroy evil. Other CV games were pretty much the same. CV 3 had the same deal plus it had multiple characters just this game has them only spread out though out a long time period. I see your concerns of what might be but I would hold off on them as of now until more information is provided especially given what MS did last time with their bait and switch routine.
The other issues I'm seeing on here from other posters is that basically a lot of people are upset that IGA is not involved with this game and it is a drastic change for them but change is needed with a series that has went on for this long. Marvel had to do the same with the Ultimate verse, but on the same token there is a lot of IGA bashing (Yes ive done it too and for that I apologize for showing my ass) but IGA did do some things right, some things wrong but he did provide a lot of games for us and there is still a chance he is still working on or is on the drawing board to continue the main timeline. But ultimately what we want is a game that feels like castlevania and so far this one seems to deliver but personally Im gonna hold off on the praise until I see how MS handles it, I'm still burned from LOS, BUT you all need to hold off on this whole this new cv sucks, the old timeline as Negumo has repeatedly stated is NOT gone and what Cox said about this story, its compared to the Ultimate universe and has not stated this is the new timeline and the old one is thrown out.