I disagree. I think that when you further establish the friendship of obi wan and Anakin it makes all the events in the OT mean more. This is obviously theoretically speaking (since the actual prequels did a terrible job of establishing them as friends).

By focusing on Anakins fall and the tradegy of it, his redemption in ROTJ means even more. So, merely explaining backstory isn’t a reason to focus on Obi Wan and Anakin but the true reason is to make so many aspects of the OT more emotionally resonant.

Do I wish the prequels didn’t focus on Obi Wan and Anakin? No.

Do I wish the prequels did the relationship more justice? Yes.