Okay, since you asked: detailed feedback.
I'm actually kind of alright with this change, but there's a few issues: first, as everyone's pointed out the transparency makes things much harder to read. Even as I type in this box to reply, the text is so much more clearer and...to be honest, this color actually makes it stand out much easier than the other gray used before. I can see you alleviated that a bit with making the comic in the background darker but it'd probably just help if you made the backgrounds to posts filled in.
The font IS the same but for some weird reason in this new theme, the letters themselves look outstretched so that's probably why everyone thinks this is a different font. I've personally had no issues with it, just giving a reason in case you're able to adjust that.
The top bar with the dropdown list being scrollable, while I appreciate having, kinda clutters up the page a bit. That's mainly due to the boxes with FORUM, CHAT, Profile stuff, et al. encompassing them being way too big meaning there's a lot of empty space. The old theme had this too, but because it didn't scroll it wasn't as noticeable, see if you can maybe change the height of those boxes. The width seems fine. Otherwise, I would just disable the scroll ability if that's just not in the cards. Jury's still out for me on the floating profile icons, I'm gonna need a bit to get used to them before I can give a say on if it's a good or bad thing, but right now I'd really prefer there be a background on that too.
The only other thing I can think of is to maybe make sure there's no spaces inbetween posts as that kinda feels unnecessary. The gaps make it easier to look at these individual posts separately but AFAIK that was never really an issue. Overall, I'm alright with this new theme, it's definitely less intrusive and not as bad as I thought it'd be, but it just needs a few tweaks to make it look more appealing.
EDIT: That and on 100%: everything looks so incredibly small. It allows for more information to fit on a single page but it really needs to be bumped up, if only by a few pixels.