I fully agree with everything said above. (measurements, maps with multiple models indicated, longer caption (BTW : 1K is fine...) )
One of things I've been asking for for a long time is the possibility to switch between two languages for the caption.
Obviously many people run into this problem : I can see models with captions in languages I don't understand (even with character sets I can't read https://skfb.ly/yM7q ). Some of my contacts don't like my models being captionned in english.
Therefore I suggest a switch with two positions one "mother language" (possibly with a user-defined language name, or flags ?) and one "english" always.
Another thing related to annotations. Actually, from time to time, I'd rather have a guided tour without any comments that tend to be in the way, just the autopilot. Ideally, including a "speed" field, or "time between annotation points".