For those spots where sunglare can happen - it is a combination of weather (clear sky) and angle/position of the sun. Both can be known from sources or calculation, and if the conditions are right for a spot, an alarm could be triggered. But... given Waze's record of not getting the automatic day/night switching right I wouldn't try to depend on it
Winter-conditions are another tale: they could be known from weather-sources, the day that it starts snowing Waze could learn from observation what happens to the traveltimes and next year, as soon as weather-sources say it will snow - Waze could adjust traveltimes/give extra timepenalties to those streets that apparently are not cleared from snow etc. Also a nice idea but it will only add to the precision of routing on 5 or 10 days per year in those areas where snowfall is a problem. Count in some extra time for the Israelis to debug this!
To sum it all up: these are very much niche-wishes that do not influence commuting by 99% of the population. Do not expect the trouble of developing this to get justified anytime soon.