Agreed, he always ends up with feature creep, but it's always something that's going to have to be added sometime, and it's always got a reason for being there earlier, usually because it's making the main aim for that release smoother or more immersive, simply a case of "well I'll have to rewrite all this when I get around to doing that... so I might as well just do that first for this release and save work later".
In the long run, this means lots of stuff he needs to do is actually already done. It also means that whenever he posts a devlog saying "Next we're doing..." I always read through it, and get to drool about what might actually
end up in the next release...
I think it's great, basically.