The first airprods were so loose in the ear I thought the entire world was playing a prank on me when I tried them out.

This must be a personal preference based on ear anatomy.

The first-gen Airpods fit my ears perfectly, and were secure. When I lost them and upgraded to the 2nd gen, I was initially upset - aside from the body being fatter (and so less comfortable in my ears) they were very insecure - I couldn't even walk around without them loosening and dislodging.

I was on the point of returning them when I saw the advice online to 'twist' them into a different position. I now use them with the stalks horizontal, and they're secure. Still a touch less comfortable than the v1s, but easily tolerable.

My experience is the exact opposite. The new shape fits less well in my ear, hopefully they've chosen the best shape for most people, but the shorter stem provides no third point of contact like the old ones!

The longer stem used to have a better chance at contacting your face for some staying power. The shorter stems don't.

The long stems were literally the same length as on their wired headphones. They encased a bluetooth antenna and battery inside their existing design.