There are a lot of quests, my quest log is literally bursting. I get that "Priority Ops" are to continue the main story directly, that the "Allies" quests are primarily loyalty missions but also some other character-arc type quests not relating to your on board crew and then there's an endless list of tasks.
Does the amount of time you take to complete particular objectives impact anything?
What I mean is, as a random example, if after saving the Moshae I then proceed to do every quest on the map before returning her to Aya, would this change anything? Do I miss out on anything by leaving it too long or are there any objectives only available within a particular timeframe?