We reject Yemen's election for many obvious reasons, and one of them is that it will not remove Saleh's family from power. Have a good look at this graph to know how dominating the Saleh's are in Yemen.
Yemenis have been peacefully protesting in millions for an entire year calling for change and demanding the fall of the regime. Yet Yemenis instead got an imposed transitional power deal, brokered by the GCC and backed by the US, UN and EU which did not address any of the revolution's demands. There is nothing in the GCC deal that explicitly outlines how the dominating Saleh family will be handing over their power, yet it only focuses on the president's role and gives him supreme powers instead. The GCC deal itself can not be challenged and supersedes Yemen's constitutions and laws.
Those who reject the elections don't feel that this farce of an election, albeit ending Saleh's 33 year rule as president, will bring about any major needed change in Yemen as long as him family and his regime are still in power. Along with his granted immunity, Saleh who is still head of the GPC ruling party can freely run again for any role, and his son too. Nor do they have faith in Hadi, the sole candidate, Saleh's loyal vice president for the last 18 years whom he selected as his successor, because he lacks the ability and perhaps the inclination to bring about that change.
More and above, sadly, no real change can happen as long as Yemen is under the US and KSA's hegemony. Yemen will never own its' decision making nor will it be able to plan it's own future, but will be run according to other agendas.
As Sultan Al Qassemi nicely put it in his tweet: