I installed Safari 10.0 a couple of days ago and noticed the same issue as many others, namely the lack of adjusting the Font Size. However, the Zoom option works fine with my iMac 27".
But so far I've stumbled over additional and very annoying issues:
1) Preferences - Privacy: Manage Website Data box used to have the amount counter of caches, cookies, and Local Storage; NOW IT'S MISSING. Previously it helped a lot to know the amount that I allow (I delete after each surfing all extras).
2) Develop - Disable Caches won't work, anymore. Even though it's marked "disable" caches appear "in zillions" after each single page viewing. The only way, so far, that I've figured out: before each browsing, unmark the Disable, then remove all extra cookies and other "crap" (including caches) by going to the above Preferences - Privacy...
After deleting, back to Develop - Disable, but as I said, it's not working, at least not completely, because there are caches coming and staying.
3) When deleting the extra cookies etc., there are two sites' crap appearing again, even though I haven't even been to one of the pages in a while. One of them is Pricegrabber, where, to my knowledge, I've never even been, so apparently some site has put it in the last few days and it keeps reappearing all the time after deleting it. The second is Intero's site, which I check every now and then.
I'm still on the latest El Capitan (10.11.6), I haven't had the "courage" to get to Sierra, yet...
Any hints?
