The point of having two HOF PG's is that we have a HOF PG on the floor for all 48 minutes. Gordon is there for backup purposes when necessary. But the ideal is to make opponents face a HOF PG all 48 min.
Before I'd sit Paul when Harden is also sitting, I'd reduce the minutes they share. It's more important to have one of them on the floor at all times than to have them on the floor at the same time.
Apparently declining foot speed according to who? His is playing exacty the same he has always played. You can't from the naked eye notice any difference. People underestimate the impact Paul has. Between Paul and Harden, they account for about 90 points (50 points scoring and 20 assists) on average. That's how you judge who is declining.
The only thing i'd like to see is Chris play more the pg doing less Harden kind of iso, he's good at it too but he's not as good as James imo, when he does i'm not feeling very comfortable but maybe it's just me and maybe i'm wrong.