"Their technique"?
I don't mean to be rude by saying this but I would've assumed by the fact that you are a Make up Artist that you are more aware than most that we are not all identically performing robots produced in a factory! Sorry, but this is a real bug bear of mine having read similar generalisations, not just about MAC but also other brands' artists, on other forums.
For example, to get a job at MAC, generally speaking, you have to already be a make up artist. They are not all trained from scratch by MAC and brainwashed into one particular technique or style. Yes, it's true, some of them are quite extreme but just as many, when they are not working on counter, work on beauty advertising campaigns, everyday fashion mags (ie. the ones that many people aspire to rather than the scary OTT ones!) etc and have very understated and beautiful taste and skills. There are hundreds of MAC staff across the UK, please don't assume they all come out of the same mold.
The ethos at MAC is "All Ages, All Races, All Sexes" - like any good make up artist, they tailor the make up to the individual they are working on.
Some people don't realise this but you can actually request an appointment with a specific artist rather than pot luck so there is less risk of getting someone with inappropriate style or taste. The staff on any counter range in experience from make up school leaver to established and experienced professional. You may even, if you do enough research, find yourself in the hands of someone who works with top celebrities on a regular basis.
Like any product or service, if you are prepared to do a little research it can make all the difference to the experience 