I give a lot of presentations, both internal to my company and at conferences. Writing presentations is easy, and results in the issues you raised (and many others). Writing GOOD presentations is much harder, and takes a lot more effort.
For me, I find the key to making a presentation that my audience will value is exactly that -- the audience. I try to figure out what it is my audience wants to learn and hear about. I'm not there to talk about whatever the hell it is I want to talk about -- I'm there to communicate something that's going to make a difference for the people in the audience (and, given audience focus, I also make sure I practice my presentations well enough that I know how long they'll take and I MAKE SURE to leave time for questions. Presenters who run out of time are just lazy).
I think presentations are like writing code -- in the end, it's really up to the author, most of the material out there is bad, and the editor (whether vim, emacs, Sublime Text, Atom, IntelliJ, or pick your favorite IDE) has little to do with the quality of the product. At most, and at best, the presentation software makes the mechanical effort a little easier.