Does it put an unreasonable burden on the ability of voters to pick the most qualified person for presidency

No I  don't think so since if this is in the US the voters have the opportunity over a long campaign to see the candidates in action and how they respond to questions so have time to form an opinion on who is best but personally as an outsider (Canadian) I often think you don't have much choice since there is seldom a candidate who genuinely is for the poor and oppressed and who recognizes the soveriegnity and territorial integrity of other countries.