Sorry, Apocalypto and Democrite, I'm not buying that. You call the removal of useful features "simplification"? No, thanks.

Marvin needs no simplification – it sorely needs even
more features (
fundamental features) than it currently has. Yes, you can simplify
access to those features – I'm all for that; but
removing useful features is inexcusable for high-end e-reader software.
Even Kris as the Marvin developer is not using the system-wide "night shift", so its availability is no justification to remove the two-fingered gesture.
As to gesture conflicts, I have long argued that Marvin should allow us to customize what each gesture does. (See AVPlayerHD for an example of software that allows you to customize every common handheld-device gesture.) That way, no conflicts can arise, because if you find that a particular gesture interferes with something, you can just completely disable it on your own device.
But to
remove a gesture from the software completely – that is unacceptable to me.

I don't need the two-fingered warmth gesture all that much (although it would still be useful for me occasionally), but I very much need the 3-fingered gesture (which I used in Marvin 2 to flip 5 pages back or forwards). I'm missing that particular gesture every single day in Marvin 3.

Again, my hope is that Kris will restore all these lost gestures/features from Marvin 2 soon.
PS: I had to laugh at reading "the best of iOS design". What an oxymoron!

I can't really imagine more execrable software design than that typical of Apple. Apple software
looks terrible (all those awfully dull shades of grey...), and it's dumb like hell as a rule. If anything, Kris should strive to keep Marvin as far removed from Apple's "let's-dumb-down-everything" and "let's-not-give-users-any-choices" software pseudo-philosophy as can possibly be managed to not get thrown out of Apple's (again, incredibly crude and dumb) App Store.