Those extra 90's won't distort the flow to your shower. If you travel that hot water supply back to it's source, you soon find that there are numerous turns and bends, changes of direction leading to the water heater.
I don't particularly agree with those air chambers; give it a number of days and those will be filled with water.
It looks like he took an existing piping system and added on to it, which is normal.
If you wanted a specific piping arrangement leading to that valve, it should of been discussed and agreed upon before the plumber started the job.
To think about this after the work is done and inspected is an afterthought, something that should of been considered before the plumber arrived.
Looks like the plumber payed attention to clean, level work and even cleaned his solder joints up well. With the cost of copper these days, I definitely wouldn't waste two pieces of copper like that for support brackets, no way.