[sesqu]

Limiting their size would cut down on the clickjacking annotations, but wouldn't deal with the hated "buy our merch!" annotations that were damaging to the video content and led to people turning annotations off. I think simply removing all links would be clear and effective, without damaging the error-correction use.

The third common use that I've seen is linking to other videos, and that's the one that YouTube's replacements systems tackle.

Another somewhat noteworthy thing is that the annotation system is tied to YouTube's channel logo overlay. Once the annotations go, it's likely that the logo will not be hideable anymore.