I will approach this question from my experience in general elections. Predictability is right at the core of the democratic principles that you might have for an election, and the predictability would feed into the notion of fairness and that everyone has an opportunity to vote.
Unpredictability has, of course, very detrimental consequences to the democratic process. One example from the other day was the curfew in Washington, D.C. at the same time as people were voting, so there was interference there between the police curfew and the actual voting. There was some exemption given to voters, but then law enforcement wasn't quite adhering to that, so it created a very unpredictable environment. Of course, that's deeply concerning.
Yes, predictability in votes, whether they're in a general or legislative context, is an absolute must.