There are two types of slides: ones that are meant to be presented and ones that are meant to be read.
In a presentation setting, I have a strong aversion to slides that take more than five seconds to digest. Slides should be used to further illustrate your point. Don't hide behind paragraphs of text. It'd be more efficient for your to send out a memo. When in doubt, please err toward more slides with less content on each one.
Slides are often the collateral left behind by consultants. As a result, consultants tend to cram more information onto each slide since they need to be intelligible after their engagement is over. This works when slides are printed and shared sitting side by side around a conference table.
Be aware of your setting and make the appropriate type of slides.