I'm not a fan of the original focuser and I think the primary mirror could use some locking bolts to hold collimation better. However, those are just my thoughts from seeing it since I haven't built on myself (yet). Maybe I will change my mind about that after I build one. I must also say that I wouldn't use the word "wrong" since if it works there really isn't a wrong way to make a scope.
I think that's totally fair. I encourage using nyloc nuts with hex bolts, or nyloc bolts alone to secure the collimation assembly.
The focuser is a curious result of my push for accessibility. It's crude, but a tensioning screw removes any slop. The point is to make it as simple as possible to make and assemble -- just a big screw. Two prints, a screw and a nut. Dead easy. But not perfect, just the best balance between easy to make, and easy to use. I myself use more complicated focusers -- I just couldn't encourage project adopters to saw a steel rod, buy a bunch of bearings etc. The remixes have all manner of crazy focusers, most of which I haven't tried. A crayford, a rack and pinion, some friction bearing stuff. My favorite is the non-rotating screw with collet.
Honestly, the community feedback and crowdsourcing on derivatives and modifications has been amazing - my own planetary images have been improved by the use of crowdsourced focuser designs. The complicated one seen here is the work of no less than four individuals working separately