Loved the new season, and if what was mentioned above that there was supposed to also be a 5th season that got slashed, it explains why parts felt rushed or that something was missing. Anyway, some opinions:
Trevor was brilliant throughout the entire season and he really got to show what a childhood of getting taught to hunt and kill monsters results in.
The entirety of Alucards S3 arc might as well not have happened and that annoys me. But I liked what he had to offer in S4, so I'm not angry at it.
They revealed the truth about Saint Germain too early. Would have loved if they slowly fed you the change over the first few episodes instead of one big exposition dump.
I loved Varney and everything around him. Definitely my favorite of the S3 and S4 newcomers.
Holy crap the music in this season was incredible. Pretty sure they used more from the games (Alucard jumping off the castle to scare some kids for example sounds quite similar to one of the games soundtracks.) Really went out big in the sound department.
The climatic fights were all real good, though the final battle could strain a bit on the eyes, but that honestly just added to the intensity.
I didn't like that it was a happy ending to so much of the main cast, including the villains. Felt really off when thinking of how S3 ended and how the world has been established up to this point.
So... did Germain die or did Trevor just assume? Also, learned nothing of Germain's friend and made his entire plot kinda... not nessesary if not for saving Trevor as Death and dagger go boom.
Sypha continues to just be a joy, and her blowing up during the "2 weeks ago" part was hillarious... Heck, the entire season was hillarious.
So... Team Belmont never got to interact in any way, shape or form with Carmilla and that annoys me. Maybe they would if the season was split into S4 and S5, but that will just be speculation.
And finally: Please say we get to see more with other Belmonts, even if there has to be a suspeciously similar substitute to Drac as the villain , as Drac doesn't seem to want to run around being all bad guy like anymore. Sure, this is the series finale to Castlevania, but it could open up for the sequel series, Castlevania: Simon's Quest, right? Right?
Also, so apparently the studio is to make a DMC series which WoG has said will be in the same universe as Castlevania, so wonder how those two will tie together.