Not worth leveling unless you really don’t have anyone else to level. I still use Griffin and Eich during w3k and the elemental quest because they are already leveled .
To keep any of them it may be worth deciding how many 4* s of each colour will your 3* troops support. Then you need to look at all your 1LB and 2LB, memblemed 4* s in each of these colours and consider whether any of these heroes has a chance of taking one of the available spots.
Don’t sleep on Maheegan’s use in events - his fiend HP pool applies to the enemies’ entire inflated HP bars, so they will essentially never heal again.
I used Brunhild alot awhile ago 2lb fully emblemd. Not much any more. Gobbler never used but is a cheep minion killer. Maheegen have leveld but dont use …you need to keep some for when events come other than that feed away .