NEW YORK (CNN/Money) - The worst Christmas in a decade has caused heads to roll at some of the nation's biggest retailers and snapped the spell on age-old business concepts.

"Last weekend we saw a massacre," said Kurt Barnard, president of Barnard's Retail Consulting Group. "There were a few shakeups in the top ranks of some retail names, and that's to be expected."

Bankrupt retailer Kmart, which filed it's reorganization plan late Friday, announced that James Adamson had relinquished his post as chief executive after just 10 months on the job to the company's president, Julian Day, who will now wear both hats.

Gap (GPS: down $0.68 to $14.69, Research, Estimates), the largest U.S. apparel retailer, replaced CFO Heidi Kunz with former Walt Disney executive Byron Politt, and Toys 'R' Us (TOY: down $0.44 to $9.59, Research, Estimates) announced the departure of the head of its U.S. operations for 13 years, Gregory Staley, without naming a successor.

Retailers have been struggling to attract shoppers through a tough holiday season marred by a sluggish economy and lingering worries of a war with Iraq.

While Barnard called it a "massacre," other industry analysts used a less jarring description -- "corporate housecleaning." But the consensus among industry watchers is that the challenging retail environment, which shows no signs of letting up soon, is crying out for fresh thinking and new leadership.

"Senior retail management is increasingly hard to find right now," said John Gifford, professor of marketing at Miami University in Ohio. "A lot of the top executives have been around for a long time and they're still working on the premise that sales are driven by value for price and assortment."

"While that's still true, price objective has moved down to fourth or fifth for buyers. Now the appeal is for presentation, excitement, a differentiated product, something that is unique and entertaining."

Sharper Image (SHRP: up $0.06 to $15.86, Research, Estimates) and Brookstone (BKST: down $0.22 to $14.56, Research, Estimates) validate Gifford's point. The makers of specialty gadgets and gizmos both posted strong December sales while many other retailers struggled.

Zu Cowperthwaite, retail analyst with Evergreen Investments, said that while executive shakeouts weren't expected to be widespread, more were likely at companies that took a hit from a bad Christmas. Some even landed in bankruptcy, notably toy retailer FAO Schwarz.

According to Barnard, the biggest casualties of the holidays were FAO Schwarz, Toys R Us, most of the department store chains, book retailers such as Barnes & Noble (BKS: down $0.40 to $18.05, Research, Estimates), whose sales at stores open at least a year, a key gauge known as same-store sales, fell 3 percent in December, as well as clothing chains like AnnTaylor (ANN: down $1.51 to $18.70, Research, Estimates).

Ann Taylor said late Thursday that Kim Roy, president of its flagship Ann Taylor Stores division, had resigned. The company's same-store sales tumbled 14.6 percent in December.

"The executive reshuffling will happen, but it will be on a case-by-case basis," Cowperthwaite said. "I wouldn't necessarily call it a 'massacre,' and I don't think we'll get a major reshuffling among the ranks of the big discount chains and department stores."

U.S. consumers aren't shopping like they used to, and visits to the nearby department store or mall are fewer and further between, industry experts said.

That trend is making it much more expensive for the big discount and department stores to operate the "big box" stores that average 100,000 to 200,000 square feet in size.

But analysts noted diverging patterns in the way that the discounters and department stores are adapting their strategies to shifts in buying habits.

"All retailers are chasing a fixed amount of consumer spending money," said Evergreen Investment's Cowperthwaite. "Most department stores are too big. Consumers sometimes get lost and give up half-way, and the store is left with a lot of inventory. Department stores also have high rent. So it just makes sense to consolidate underperforming stores."

Federated Department Stores (FD: down $1.14 to $25.64, Research, Estimates), which owns Macy's and Bloomingdale's, said last week it was shutting 11 stores, including seven Macy stores, as it consolidates its Rich's and Macy's chains in Atlanta.

On the other hand, discount chains such as Wal-Mart and Target (TGT: down $1.05 to $27.70, Research, Estimates) are increasing their square footage through their "superstore" and "supercenter" concept -- offering both fresh food and consumer staples like a grocery store-- because they want consumers to go there every week and drive up traffic.

Cowperthwaite said the strategy makes sense for the discounters because their rate of return per square foot is much higher than that of the department stores.

Among the discount and the wholesale retail group, Costco (COST: down $0.71 to $28.90, Research, Estimates) has the highest sales at $700 a square foot, followed by Wal-Mart at $400 a foot and Target at $300 a square foot.

Meanwhile, upscale retailer Nordstrom (JWN: down $0.45 to $18.19, Research, Estimates) led the department stores with the highest sales at $300 a square foot, followed by J.C. Penney (JCP: down $0.35 to $19.39, Research, Estimates) at $230 a foot, Federated at $200 and May Department Stores (MAY: down $1.05 to $21.11, Research, Estimates) at $180.

"Those that are losing market share are trying to make the box smaller, like Kohl's (KSS: down $1.50 to $53.75, Research, Estimates) did. Discounters are gaining market share and they're expanding to attract more customers," Cowperthwaite said, adding more weak stores would be shuttered this year.

Kohl's, one of the fastest growing specialty retailers, operates about 455 stores and plans to open 80 new ones this year, including 35 stores in the first quarter.

"Kohl's did a few things that made the shopping experience easier," said Barnard. "They introduced shopping carts, centralized checkout counters and an easy-to-shop store layout."

Miami University's Gifford said a simple thing like introducing shopping carts revolutionized the shopping experience at Kohl's and made it a more family-friendly store.

"The new concept for department stores and specialty stores has to be a smaller footprint, shopping carts, a 'spoke and wheel' layout where an inner circle leads to an outer circle instead of the tiresome grid layouts, and central checkout systems," said Gifford. "Federated is making similar changes, by introducing a checkout counter for every seven departments within a store."

Department stores can cut costs by as much as 20 percent by shrinking their size from 100,000 square feet to about 55,000 square feet.

Meanwhile, specialty store chain Bed, Bath & Beyond (BBBY: down $0.52 to $33.92, Research, Estimates) focused its strategy on "wallscaping" in its stores, making greater used of its perimeter walls by mounting products on display units that go farther up the walls.

Industry experts said that the wallscaping display technique is a good way to maintain just-in-time inventory that can cut backroom inventory by as much as 50 percent, push sales and help retailers maintain profit margins.

"Slashing prices is not the only option," Gifford said.