Are open-world games getting too big?

Assassin's creed, you can be riding a horse or running for a good 15minutes+ to get to a destination. RDR2 was a huge game that felt like 30minutes+ to get anywhere that I gave up with it.

Is open world becoming too open world with lots of vacant/empty space in games?

Yes, I think some open-world games have become too big for their own good. Exploring is fun, but when huge areas contain little more than repetitive tasks or empty scenery, it starts feeling like a chore.