You did the final battle against ME4 villain with all people you helped through the game helped you in different stages. What did you expect? I mean, can't ending be better than that.
Also, devs gave you have some postending chatty.
If you mean mysteries unsolved, expect them to be answered either through a DLC or in ME5. I vote for ME5, but if Bioware's plan is 40 hours long expansion like TW3 had, won't object.
And your list of questions is unbelievably short. My list is much bigger, lemme list just some of things I'd love to see in an huge expansion or ME5:
- The resolution of that one particular murder
- The Quarian ark
- The revelation of the mysterious benefactor
- A way to nullify the scourge
- Advent and Aurora resolution
- The lategame sattelite made by Initiative technology yet not belonging to any of known "factions" resolution
- The camp on Eos near site #2 resolution or fixed bug that prevents it to work
- tech Danny Messier post Eos whereabouts (so he does go where he says and not ending at Krogan gunpoint on a completely different planet)