By Mimosa Spencer, Elisa Anzolin and Tassilo Hummel

PARIS/MILAN (Reuters) - A slump in luxury fashion is prompting designer reshuffles at top houses Gucci, Chanel and Dior to reignite heat around their brands - while avoiding too radical a reset that could confuse affluent shoppers.

The stakes are high, as the 363 billion euro ($395.09 billion) global luxury goods market grapples with its lowest sales rates in years with after an economic slowdown in China and rising inflation elsewhere make high-end consumers more reluctant to splash out.

"Brands are under more pressure than ever to balance creativity with commercial viability, while also maintaining relevance in a constantly shifting market," said Lydia King, group buying and merchandising director at upscale British department store Liberty.

Kering-owned Gucci and Chanel are placing their bets on rising stars from much smaller labels, with LVMH's Dior likely soon to follow suit. But new designers face the tricky task of bringing the right dose of renewal, with investors giving them little time to establish themselves.

Last week's announcement that Gucci had appointed Balenciaga designer Demna to head its design teams sent Kering shares down over 10%, wiping around 3 billion euros off the group's market value.

In an era of "superstar" creative directors, designers shape the identity of brands, even overshadowing a brand's heritage, said Jacques Roizen, of consultancy DLG.

Many analysts had lobbied for bolder fashion at Gucci following a two-year push upmarket with more classic designs, but investors worry Demna, 43, who brought buzz to Kering's smaller label with high-end streetwear styles, might not be the right fit.

Creative directors are redefining "not only the aesthetic direction but also the positioning and clientele of the houses," said Roizen.

As China remains subdued, luxury brands are pinning their hopes on the U.S. market this year, although signs of economic uncertainty are creeping in.

Chanel, which is privately owned, is bringing in Matthieu Blazy, 40, after his successful run at Kering's Bottega Veneta. He faces the daunting task of ushering in a fresh design approach, overseen for decades by Karl Lagerfeld, and then by longtime collaborator Virginie Viard following Lagerfeld's death in 2019.

The importance of the creative director can vary by brand, said Flavio Cereda, who manages GAM's Luxury Brands investment strategy.

Since Viard's abrupt departure last year, Chanel has emphasized trademarks, sending models down a runway shaped in its interlocking-C logo or wearing clothes adorned with signature black bows - at Lagerfeld's preferred venue, the Grand Palais in Paris.

INDUSTRY-WIDE CHANGE

LVMH has yet to officially announce new creative leadership at Dior after menswear designer Kim Jones left in January, but is likely to soon hire a new designer, expected to be Jonathan Anderson. His departure from Loewe was announced on Monday, but LVMH declined to comment on Anderson's future role.

There are also new faces at a host of smaller brands, including LVMH's Celine and Givenchy, and Donatella Versace, 69, is stepping aside at Versace after nearly three decades, replaced by Miu Miu's Dario Vitale.

"Clients don't know where to go anymore with all these musical chairs," said Yannis Ouzene, a sales assistant for a major European brand on the Avenue Montaigne in Paris, home to some of the most exclusive fashion houses.

"I don't recall seeing such a significant shift in creative leadership across the luxury industry," said Achim Berg, fashion and luxury industry advisor.

Change will sweep through studios, merchandising teams, marketing departments and design teams -- but takes time, with no visible impact likely until next year, he added.

Brands need to be wary of bewildering clients with "too drastic changes in the aesthetic language of a brand," said Federica Levato, senior partner at consultancy Bain.

For Chinese shoppers, the "here and now" of a brand's design is more important than its historical context, while Western shoppers place "significant value on the continuity of a brand's identity", said Roizen.

For some, the designer is not a deal clincher.

"I don't care who the designer is," said Stephanie Gold, an American tourist in Paris who recently purchased a pair of prominent Dior glasses. "I don't like to buy what everybody has."

The luxury sector overall - which averaged annual growth of 10% over 2019-2023 - is expected to grow around 4% in 2025, with sales to Americans accounting for over a third of the global growth, up 7%, compared with a 1% decline from the Chinese, based on UBS estimates.

Olivier Abtan, consultant with Alix Partners, says brands have to be careful not to wait too long before shaking things up.

As the market awaits word on Dior's new design chief, and LVMH grapples with shopper fatigue buffeting the industry, some wonder whether design change at Dior, which lags group heavyweight Louis Vuitton, should have come sooner.

Change needs to be made "as soon as a brand senses growth is slowing," Abtan said.

($1 = 0.9188 euros)