NEW YORK -(Dow Jones)- A combination of Citigroup Inc.'s (C) and Morgan Stanley's (MS) brokerage operations would create the country's largest broker. But while the deal may improve Citi's capital ratios, some observers fear the boost would not solve Citi's capital issues. For Morgan Stanley, which presumably would become the majority owner of the entity created with Smith Barney, the deal would put the company in a better position to take advantage of potential disruptions created by rival Bank Of America's (BAC) integration last week of Merrill Lynch & Co. Yet even the consideration of separating from its Smith Barney...