Committee members, what made the winner stand out?

If I were you, I would consider avoiding the mentality "technical perfection above all". Reliable, strong technique does not live in a vacuum. Technique and musicality go hand in hand. A good musician is a good musician.

Every round is an opportunity to showcase yourself and bring your music to life. Committees genuinely want to hear everyone's best. We want to hire. We know that mistakes happen to everyone even at the highest level. But what is not permissible? Serial mistakes. These are mistakes (or rather unwanted habits) that present throughout an individual's audition. Some examples of serial mistakes: intonation in the cracks (i.e. not resonant), rushing short silences during rests, omitting dynamics/articulations, etc.

Mock auditions are key. Play for as many people as possible and share your observations with one another. Audition preparation is all about developing a highly critical, yet judgement-free ear and to always strive for greater consistency. Good luck.

Is it safe to say that my first round should be "technical perfection above all", and leave any potentially distracting stuff such as musicality or creative liberties for later rounds?

Super fair question, the lack of adequate feedback from committees these days is a real shame. When I sit on a committee I take it really seriously and write detailed notes for every player, trying to be specific about what I liked or didn’t like about their round. I always offer my comments to our PM who collects and distributes them to the candidates who ask. It feels like the least I can do for all the folks who travel and come audition for us. But it surprises me how many candidates don’t ask for comments, FWIW. Keep asking for comments every time, it’s your right.

I think there is a big difference between what stands out between a round that is good enough to advance from a prelim/semi, vs a round that is worthy of being offered the job. In the earlier rounds, there is a natural weight given to more foundational elements such as time, intonation, rhythm, articulation control, note accuracy, etc. Being able to communicate appropriate musical ideas and an understanding of the score are nice, but that is simply a bonus if someone plays in time and with quality technical control.

However in a final round, I find that less weight is given to those fundamental things. More leeway is given for mistakes in intonation, rhythm, articulation, etc because these things have already been proven in earlier rounds. Instead, the committee often becomes attuned to musical personality, risk taking, style, and artistic authenticity. I have heard many final rounds that I would “advance” in a prelim or semi but are not sufficient to be awarded a job. At this point we are selecting a lifelong colleague, and that means there are other priorities besides technical precision - things that matter in the day to day of a job, like flexibility, adaptability, focus, recovery after a mistake, commitment… when your playing is technically solid enough to consistently advance to final rounds, then you must seek that final level of polish and artistic command that will win the day.

Sense of time. I want to feel comfortable when listening to someone. Their sense of time must be poised, spacious, and with an awareness of the score at large.

A beautiful sound with pure intonation is required to reach a final round, but, in my experience, the winner is someone whose "time feel" is logical yet flexible. They have ownership over the subdivisions and are never in a rush. They prioritize long phrases. Bonus points for good style...

Too often, the small compositional details fall by the wayside. Perfection is many little things done well. The candidate who can bring those details to life will be noticed.