I actually think there's a benefit to older/slower cameras with "bad autofocus" - they force everyone to take a "time out" slow down - think about what they're doing and why... That can make a big difference between average work and amazing work!!
I agree, I never use AF for landscape anyway. Now certainly the 5D4, R5 is a pretty significant improvement over the 5D2 in dynamic range, and a few creature comforts but for landscape shooting the actual process isnt much if any different.. Live view, zoom in to the spot you want critical focus on, and manually focus. I don't miss needing to use mirror lock-up though 
Ummm... for high DoF shooting the focus guide will do a great job in a pinch, but more often than not I choose to focus manually on a zoomed view. It's more deliberate, and why be in a hurry.

















