toby
It appears that Microsoft made some changes with 2016. I don't store but two or three icons on the QAT so I didn't notice the difference. I googled excel resize QAT and found several posts on this subject. Apparently you can increase the QAT to two lines or there is some functionality with Touch/Mouse. Take a look at the links that come up when you run the Google Query and you might find a suitable answer.
BTW: I use Alt F8 or just one Icon on the QAT to open all my macros. Personally, I find it less clutter and I cannot remember the different symbols I establish for each Icon.