Isn't unifying the company's identity the exact opposite of breaking the company up? Will the move do anything for the company's lagging stock price (shares have risen a total of about 5% over the last 5 years)? Highly unlikely.
Without a break up, Citi sports a 6 - 7 percent earnings growth rate and a 12 P/E multiple. Such a ratio seems about right for that type of growth. By breaking up into smaller pieces, it would be much more obvious to investors that some of Citi's businesses are growing much faster than the entire firm as a whole. In that case, higher multiples would clearly be afforded to certain divisions.
The result would be increased shareholder value, not to mention better growth prospects, given that it is much easier to grow a bunch of separately run, individualized, smaller firms than it is an enormous one. Just giving each business its own colored arc really doesn't accomplish that feat quite as well.
C 1-yr chart
Disclosure: Author has no position in the above-mentioned company