* President seen stalling peace talks on northern Mali
* Two years after coup, 350,000 still displaced
* North Mali seen as key to fighting Islamists in Sahel
* Experts sceptical on pledges to fight corruption
By Emma Farge
BAMAKO, March 12 (Reuters) - President Ibrahim Boubacar Keita won power with a pledge to resurrect a "strong and united" Mali from the ashes of a war against ...