Recently, a client insisted on using Google Slides for our presentation design project, especially because of its good collaboration features. Instead of starting a presentation in PowerPoint, then converting it to Google Slides, I took the native approach, and created a presentation from the ground up in this application.
The design of Google's office user interface has improved a lot over the years. Things look beautiful and work fast and snappy. Still, the Slides product is full of little issues that 1) slows down a pro-user like me, and 2) makes it harder for the layman designer to make good looking documents.
Because I invested my own hard-earned money in my presentation app SlideMagic, I feel a bit hesitant here to spoon feed a ready made upgrade suggestion list to a multi-billion dollar software developer with the world's smartest programmers ready to implement them....
In 2017 - leaving minimalist SlideMagic aside - I think PowerPoint is again/still the best slide design software out there (also on Mac), better than Google, better than Apple Keynote. The main criterium here is not feature set, but workflow.
There have been many of these types of posts on my blog over the past 9 years, and I am sure there are many more to come as products continue to evolve.