The more complex an issue, the less disagreement there is. The simpler the issue, the more disagreement there is. One would hope for the reverse situation, where disagreement was proportional to what was at stake, but the reality is different for a very good reason.
People can only really disagree vehemently about something which they can make reasonably credible statements, or at least statements that aren't immediately brushed aside as being empty. Otherwise, no one is going to stick their neck out to look like an idiot, or they will simply be incapable of finding a vector of attack since they do not understand what is going on anyway.
Conversely, if a problem is so insignificant that everyone can (and does) have an opinion, then everyone will feel compelled to state that opinion, if only so they feel that they are involved and to show to others that they are involved.
An good story about why is described as [Why should I care what color the bikeshed is?], where it's easy to get a board to approve an atomic reactor, but impossible to get them to approve a bikeshed; see also WikiPedia:Parkinson's_Law_of_Triviality.
Before we get too far, let's DefendAgainstCynicism. We AssumeGoodFaith that everyone wants to contribute, but obviously there are more people capable of contributing to the simple things than there are experts capable of contributing to the difficult things. So, there is obviously more discussion around simple decisions that should in fact be made quickly.
A good solution is to work hard to train people on hard decisions rather than just letting experts make the decision. The expert's job is not to decide, but to educate a wider population who in turn decide. While this will be biased by the expert's own biases or failures to teach, in practice the wider population will ask a lot of hard questions. The role of the population is not to kill the messenger, but try to do some BarnRaising with the expert to elicit the most amount of digestible information.
Parkinson, C. N. (1958). Parkinson's law: The pursuit of progress. London: John Murray.