It is better to look at it like this:
1. How do the mobs of the mission challenge your power sets(or not)?
2. How does the mission type challenge your power sets?
3. How does your level in the game progression challenge?
4. How does your choice of powers within the 1st 2nd and other power sets change your mission?
5. How does your game play style(aggressive, conservative, middle of the road, etc) change things?
6. How does your slot and enhancement choices factor?
7. How then does 1-6 affect it in different combinations there of?
In other words no one can accurately give you a definitive answer because it depends on a recipe of 1-7. What you can do at level 10 with your set on hellions can vastly be different from what you are doing at level 47, with a larger swath of choices of powers(and which choices made there in) against say crey or carnies or something else.
Most of the time, the way you learn your answer is through experiential learning via trial and error because (especially as new to this return to the game as most are) the chance statistically that someone will take the same power sets and power pool etc choices, slot them same and make choices to fight the same missions and same mobs?