I currently own a BMW X5 and love it, but I’m thinking of switching. I tested the Land Rover Defender a few years ago - it looked great, but felt too uncomfortable. Has its comfort improved? I’m not interested in the GLE because it lacks a sporty feel. Could you recommend some options that combine comfort, performance, and a sporty edge?

The Land Rover Defender hasn't undergone any mechanical changes since its launch, so it is unlikely its ride comfort will be any different from what you experienced. With large SUVs like these, as I'm sure you know from your X5, wheel size and suspension choice also have a huge bearing. 

Air-suspended Defenders ride significantly better than steel-sprung ones in our experience, so make sure you have tried both before making your decision. It isn't particularly sporty, though, and if that is what you're after, you might want to consider moving a bit higher up and checking out the Audi Q8, Porsche Cayenne or Range Rover Sport.