I attended graduation concert on Western Classical Flute. Player was breathing very loud but I've heard it only because concert hall was very small. Is loud breath intake assesed as bad technique or not?
Generally, yes, it is considered less-than-ideal performance practice for a few reasons:
That said, if done expressively and with tact, hearing a performer breath can also create the opposite effect: giving the music a more passionate, human quality and therefore enhancing the overall experience.
I always encourage people to take large, open, deep, relaxed breaths. (It's good to use that many adjectives!)
Hope that helps.
I would add to @jjmusicnotes answer that if you can hear the breath, then something is likely interfering with your intake of breath - which is not good. One of my old instructors said "Think 'HO' in reverse". This means to shape your throat and mouth into the same shape as when you say 'HO' and then breath in. Try it!