There should be a validation requirement that the first and last frames match the respective current and next slide.

There are a few in there that are disorienting because they jump. Most of those that do have jumping problems look like they are treating the source images as (or stretching to) squares.

There is already! However it is not yet filtered in the current homepage but this will be ASAP.

as a proof: https://glsl.io/transition/a830822b23e846e25d2d

see that there is already some warnings ;-)