As a frequent flyer (Qatar Airways Gold Card) ,regularly flying Business, I don't really have a problem with tattoo's. I help the crew when they arrange my table, I'm polite when they ask questions (ie take off my earphones), quite frankly they are there to make my flight pleasant, I am , as a passenger (In my view) there to try and make their work as easy as possible.
I don't care if they look like the aftermath of a bus accident, what I do want is someone who can get me off that aircraft if the s##t hits the fan.
They are there not to look pretty (male or female), they are there for my safety. The meals, pleasantries etc are secondary to that.
Safety first, tatto's second.
Just my point of view as a passenger.