FOR all of its problems, the United States banking industry is looking increasingly good to many investors.The guarded optimism comes despite criticism from Washington about high interest rates on bank credit cards, unease about problem real estate loans, and concerns that some financial institutions are reluctant to make loans, even to credit-worthy borrowers. The failure of banks to issue loans is often cited as one of the key contributors to the current downturn, although it is not disputed that loan demand fell off during the recession. Still, there are a number of reasons for a somewhat upbeat view of the banking industry. Assuming that the economy does not substantially worsen during the months ahead, the banking industry is expected to come out of the downturn in a fairly advantageous position, compared to other major US industries. Traditionally, bank stocks often rise in the period following a recession, as the pattern of lending slowly builds back up and credit costs return to a more "normal" level. The banking industry is now in the "midst of a multi-year bull market," says Thomas Brown, a bank specialist with Donaldson, Lufkin & Jenrette Inc. "Bank earnings were terribly depressed in 1989 and 1990," Mr. Brown says. "But earnings are now recovering and should continue to recover. If the economy were to head south [in a 'double-dip' recession], then the earnings recovery would be delayed for the industry. But it wouldn't be aborted." Despite the improving earnings picture for most banks, federal officials still expect some failures in the period ahead. A number of banks acknowledge that they face a rising level of problem real estate and mortgage loans, particularly along the Eastern Seaboard, where the impact of the recession has been most severe. Last week, for example, the Mortgage Bankers Association announced that residential mortgage payments late by 90 days or more grew at the fastest rate in over five years during the quarter ending Sept. 30. Real estate foreclosures during the third quarter were also up. Still, the banking industry as a whole saw its equity capital and loan-loss reserves grow during the quarter, the result of better profitability on outstanding loans. The increase in capital and loan-loss reserves is felt to be sufficient to offset any unusual upsurge in foreclosures during the winter. Moreover, the industry has substantially reorganized itself during the past several years, Brown says. Back-office operations have been extensively computerized. Unprofitable ventures have been dropped. A number of important mergers occurred, such as the combination of Chemical Bank and Manufacturers Hanover here; Chemical and Manny Hanny are now starting to consolidate their staffs and eliminate duplication. Officers for the two institutions say the restructuring will strengthen the combined company and lead to savings in excess of $650 million. Restructuring within the banking and financial services sector is expected to continue - and to affect financial markets in general - well into the 1990s, according to Charles Clough, chief investment strategist for Merrill Lynch & Co. In two recent studies for Donaldson, Lufkin & Jenrette, Brown and his associate Frank DeSantis Jr. saw favorable growth prospects for both the big money center banks, and prominent regional institutions. Costs related to credit problems are seen as falling. Bank expenses are down. And there is "healthy consolidation." Bank earnings are expected to grow, assuming that there is growth within the overall economy. Henry Dickson and Lawrence Vitale, analysts for Kemper Securities Group Inc., also see consolidations as beneficial. Looking at the Midwest, the Kemper analysts say commercial and industrial problem-loans may continue to increase for some banks. But the number of "problem banks" has stayed relatively level, underscoring the basic stability of the industry. In the Western US, according to Kemper, economic growth has slowed in all major banking markets, but capital ratios for the banks have been improving.