Well IMO i would absolutly prefer that only cabinet member's can run for president. Believe me ,it's not an easy job ,it's not to under-estimate.
I have some requirements (quickly) written here that a candidate for president must have:
1 time
2 responsibilety
Believe me ,there is a lot of work to this game.Ask my leaders like Animepornstar ,Sixchan ,Unknownsoldier and other's.
3 continuality
If the president is gone for a certain time ,the game stop's.
4 vision in judgement
A president must make some important dicission's ,he must know what the effect of them will be on the long term.
5 diplomatic gift's
You will have to motivate youre leader's to do their work,and you will have to keep good ties with the moderators

6 flexibilety
This game is at an experimental fase. The president is in control of the game.He must construct easy way's to organize the beraucracy of the decission making and integrate them into the actual game in a flexible way.
7 Leadership
The ability to lead the way if something must change.Or to help youre leader's if they have question's.And to make proposal's on how to organize the work.
technical:
1 The abbilety to post hyperlink's and screenshot's
2 The abbilety to use information media like mail and pm
note: this seems obvious ,but not all member's have the knowledge to do these things.
In general ,i even say the technical requirement's are a must if you want to go for a kabinet position.
I try my best to be a president.And i hereby announce that i will run for a second term.My biggest pro: experience ,and believe me ,experience is very important in this game.
As for cabinet position's ,i will most probably vote for the leader's of my gouverment that have done most work ,as i believe that they will make the best option to choose from.
And again i must stress all the member's of this game: Responsibilety is a very important thing here.If you wan't to run for a position ,you must be prepared to do the work that is involved in it.
Leader's have a certain power though.They decide what the option's of a poll are ,and this is a fair power.You will notice that later into the game.The option's of the poll's are made up by the leader's, this why they could even push the poll towards a certain option.

And i think this power is a fine addition to the game ,and it make's the leader position's interresting.Especily those position's of millitary leader, diplomatic leader,Domestic leader or exploration leader ,because the dicission making it these department's must be flexible.The science leader has less work ,but also less power.The millitary leader has most individual power.You may not know what i'm talking about now ,but you will notice it later.