Looks good:
the only issue i've had with these types of bags is that they kill my lower back due to bad strap placement.
It looks similar in this situation.
It could be interesting to report on the actual wearing comfort once you've tested it with your gear in it!
concerning baggage theft / damage to your gear:
Just make sure anything fragile is in your hand luggage (computer / mask)
I asuggest carrying regs in hand luggage, but if you insist into checking them in, maybe try to disassemble it and just take a small wrench with you for reassembly on site so there's no possibility of hoses being damaged.
And towels are your friend! Just towels and correct placement. They will basically cushion an elephants' weight if correctly placed in your luggage
If you're paranoid of baggage theft, just get a little padlock that will dissuade a first time opportunist.
But if someone really wants to steal from you it's the same as in normal daily life: make sure you have insurance because a real thief/criminal will always be able to get your stuff.