The dialect Arab leaders choose, either classical or colloquial, matters more than one might think:
Qaddafi’s populist rhetoric was matched with popular language. His use of local dialect in political contexts made him seem closer to ordinary people, but also masked an authoritarian streak. This style, more associated with the old guard of Arab nationalist leaders like Gamal Abdel Nasser, connected Qaddafi to the politics of the 1960s. With his demise, Libya, too, has shifted toward the linguistic center.
Others are more tone deaf:
Zine el-Abidine Ben Ali, the former president of Tunisia, gave his first speech in response to popular unrest on December 28, 2010, in stiflingly literary Arabic, with full inflections and no emotion (although there is an amusing moment half-way through when a phone rings in the background for nearly a whole minute). That he recognized the alienating effect this had on listeners is clear in his attempt to tone down the formality of his subsequent speeches, although in vain.