In a representative democracy, elected leaders need to be able to use their judgement to decide what tools they and their lieutenants should use to come up with and implement the policies in service of what the voters' want.
Who is supposed to do this certification? How is it supposed to be binding?
Sure, that's what elections (and the courts) are for.
Leaders can decide to be even more accountable and transparent, if they think that'll increase their chances at the ballot box (or if they are just nice people).
Your idea seems to be outright incorrect. We need transparency to stop bad things -> Bad things do not help at the ballot box -> We won't be given transparency through the ballot box (unless there are no bad things in which case we didn't really need it). In other words, if what you say is true (and it seems it unfortunately is), we won't ever get transparency and bad things will happen unchecked and unseen.
Instead of elections I think transparency should be determined by rule of law so everyone has to participate, even those that would like to hide their bad actions.
If people want 'bad' leaders, they can elect 'bad' leaders. That's democracy for you. ('Bad' in the sense of people you and me disapprove of.)
It's obvious to anyone that Trump is intransparent at best, and most likely corrupt. People still voted for him. And Trump isn't even hiding his bad actions all that much. I mean, he might be hiding some details, but it's common knowledge that he is doing 'bad actions'.
