Stunning slide decks include only necessary elements.
Audiences will read, or attempt to read, everything on your slides. From the moment your slide appears, the reading commences. The more content initially displayed, the longer the reading continues. For that period of time, the majority of the audience is single-tasking, and all the words you speak become background noise.
When including words on your slides, remember they are called bullet points. The tendency is to use sentence points (and read every word on the slide to the audience), which will require more attention from the audience away from your message. Bullet points contain the minimal amount of words you need, no filler words, few conjunctions, and minimal to zero punctuation.
Stunning slides keep content to the absolute minimum.