Thanks for the love!
Couple of thoughts about hanger alignment and the tools to do it.
Precision is king, with modern drivetrains the hangers need to be pretty damn straight, less than 2mm honestly. You're simply not going to do that with a tool that has a bunch of play or something that requires you to eyeball it. Honestly, if you're not going to get a precise tool you are better of just using an adjustable wrench and getting it good enough.
The rotating head is nice but certainty not mandatory. It really comes in handy when you're working on bikes with racks and/or fenders where there's lots of stuff in the way.
A locking indicator is pretty nice as it keeps you from second guessing your measurement. Don't try to move the indicator out and back in to what you think is the same spot. It's not going to be the same and your results will suffer.
The rear derailleur thread is one of 3 things that are truly standardized on the bicycle (bottle boss spacing and chain pitch being the other two). Introducing other variables into this process could lead to tools that are more likely to become obsolete or need additional parts to maintain compatibility. Something to think about in this ever evolving world of wheel sizes, axle spacing and axle threading.
Finally, an extremely strong majority of factory techs for drivetrain manufactures use our HAG. This includes Shimano who make their own tool! If that doesn't convince you what's more trusted I don't know what else will.