WHAT bothers today's woman most about that huge array of ready-to-wear on the market? Diane Freis has a pretty good idea. ''Fashion has become so streamed, that often she asks herself: what is it exactly that I'm paying for? In Hong Kong, where renting shop space is becoming more and more expensive by the second, the answer is often: the landlord.'' By ''streamed'' the locally-based American designer means the uniformity that has engulfed contemporary fashion. Chop away the labels from say, three pairs of insanely expensive ''designer'' jeans - or for that matter, your basic shirt, skirt or blazer -mix them up with the same number of modestly-priced mass market jobs and even a terminal fashion addict would be thrown into confusion. The thought of such a cynical exercise doesn't bother Ms Freis. Why should it? For best part of two decades, she has reigned as the one-size-fits-all queen, creating clothes so distinctive they might as well have her name plastered all over them. True, those elasticated numbers are the essence of simplicity in terms of garment construction. But Freis' feel for colour, fabric and ornamentation has always kept her in a class of her own. And now she has launched a new line which should truly confound all the copy-cats who have sought to cash in on her global success. It's called Freis Spirit and is a total departure from the winning formula which has served her so well: finally fitted clothes from the designer whose creations could have been based on Parkinson's Law. ''There is some elastication, but most of the clothes have been cut to size,'' the designer said at her Kwun Tong headquarters yesterday. ''It's a younger, fresher, more spirited collection aimed at the executive woman aged from about 25 to 35 though it should appeal to a wide group. ''We'll hit the European and American markets later. First, we decided to test it in Asia, because we have representatives in all the key cities in the region.'' Diane Freis thought long and hard about the best place to launch her new line in Hong Kong. A big, glossy shopping mall with the added attraction of novelty would be perfect, she decided. She found just the place. ''Times Square in Causeway Bay. I think it has the potential to be as successful as Pacific Place and it seemed right for Freis Spirit.'' Her first collection, in lightweight merino wool and wool crepe, went into the shop in November, just in time to cash in on the current season. Meeting the deadline was a frantic scramble, but the response to the colourful knitted separates has been strong and Freis is confident her Spring-Summer '94 collection will sell even better. ''The orders throughout Asia have been superb. In fact we had to double them because everybody was so enthusiastic. ''I think Freis Spirit will do well in China. We recently opened a shop in Shenzhen and also have an outlet in Beijing. ''Our policy is to keep the line separate from the Diane Freis label because the customer base is completely different, though no doubt there will be some overlap.'' As her samples for Autumn-Winter '94 reveal, there already has been a cross-fertilisation. The look is vintage Freis - lots of rich colour and embroidered detail - but along with the flexible dresses, skirts and pants will be structured jackets and a svelte new air. It's the most mature collection Diane Freis has yet created - still entirely feminine but noticeably sleek and sophisticated - and she gives due credit to her fabric suppliers. ''This year we decided to go to India for inspiration and the fabrics we found at the New Delhi fabric fair were exquisite.'' From her earliest days in fashion as the Art History student in California who discovered she had a flair for design, Diane Freis has always been an artist who uses clothes as her medium. Nothing has changed - except for a few responsibilities like raising three children aged between three and 10, and running an international business which stretches from Sydney to San Francisco. She has no plans to wind down or quit the city she has long called home, says the designer who started out with a tiny workshop in Mongkok back in 1978 and once raised eyebrows with her flamboyant clothes and hairdos. ''Almost from the day I arrived here, I've never seen myself leaving Hong Kong and retirement is not a word that has any meaning for me.''