Can anyone who doesn't use Lightroom actually distinguish the differences between a slideshow created in v5 vs v6?
Well in LR6 we FINALLY got
Ken Burns effects so yes, probably. That said, this module is still pretty lame and weak compared to other solutions.
For me, the 'improvements' are near negligible considering the module has languished since nearly the inception of Lr.
If you remove the new features that are part of Develop and thus ACR, you're pretty much spot on! If John would simply examine the history of 'features' between LR4 and LR6, he'd see the entire list got shorter and shorter as the release number raised. Subtract Develop/ACR features, there's not much there.
According to Victoria's FAQ, this is the exhaustive list of new stuff in SlideShow:
Slideshow
• Pan & Zoom – Ken Burns Effect
• You can now add a pan & zoom effect to your slideshows, also known as a Ken Burns effect.
• You can change the amount of movement. • Music Multiple Audio Tracks & Sync Timings
• Audio settings have now moved to their own Music panel.
• You can add up to 10 music tracks to your slideshow.
• You can sync the slide transitions to the music, so it intelligently changes the fade time based on the music beats.
• Aspect Ratio Preview
• Slideshows can now be previewed at your screen aspect ratio as before, or they can be previewed at
your intended output aspect ratio (either 16×9 or 4×3). • Preview Quality
• You can pick the preview quality, depending on quickly you need to start the playback.
• Export is always done at full quality. • Other minor UI changes
• There’s a new Music panel and the Playback panel has been rearranged. • Manual vs. automatic slideshow are now buttons instead of a checkbox. • Slides slider now called Slide Length.
• Fades slider now called Crossfades.
• Repeat now called Repeat Slideshow.
Massive engineering? Lots of love for Slideshow? Not really.