Of the big heroes, I think they fall into 2 pots: People who can do damage which avoiding spellcasters, and those who deal a lot of damage but aren't worth immobilising.
Pot 1 contains stuff like Glorfindel with his Armour of Gondolin. This increases his magic survivability and means he can do what he does best. Another one is something with an Elven Cloak, like Thranduil on foot. He can still dish out a lot of damage, but can also avoid a bit of spellcasting.
Pot 2 contains things which aren't worth keeping tied down all game. The other side has a lot of points spent of a spellcaster; if your hero is cheaper, they won't pay for themselves by stopping you, which is what you want. Good guys to not be worth stopping who can still lay on the hurt are captains with +1 to wound or Strength 5. Hasharin and King's Champions also fit this bill well. Named heroes in the mid points range are also excellent, because they are cheaper then the magic user sent to stop them.
And those are my rambling thoughts. I'm sure I said something here which some of the more experienced players will disagree with, but since I play with only 1 other person, our meta is quite separate from the general meta
.