It would seem that one would not want to wait until the week of a presidential election–or worse still, between rounds of said election–to define the powers of the president-to-be. But then there is Egypt.
I believe it is unusual for a president to be elected before a constitution–even a provisional one–has been enacted. Normally, there is a constituent assembly, during which time a provisional government remains in place, as in Tunisia currently, or else a constitution is negotiated prior to any elections (as with several Eastern European and African transitions of the 1990s). In fact, the only other examples that come to mind of presidential elections preceding a determination of presidential powers are Nicaragua (1984) and Romania (1990). At least in the latter case, the the first president was elected to only a two-year term (as was the concurrently elected constituent assembly).
Meanwhile, apparently the voter turnout in this week’s first round of the presidential elation was only 50% or even just 40%. Either figure would be really, really low for a first presidential election in a transition to democracy–or an alleged such transition.