In order to make them more effective, their specials should last for 4 turns, not 6 and increase the amount of damage for both by 45 points. That would put them on par with some of the more new heroes.
I’m not disagreeing with your suggestion but idk how viable it would be , as the newer heroes are all made to be BETTER heroes with higher attributes/ new specials - you know for game progression ( people’s interest 4 better heroes )
Classic heroes , are not all bad and can still be used - but it’s difficult to say if they will be buffed . Unless there is serious game imbalances .
Ps those heroes you mentioned aren’t broken lol 
I see what you’re saying about broken, so I amended the title.
Plz give them an increase of some sort. Kelile was my first 4* I was excited to have her… now I wish I wouldn’t have wasted time on her
I don’t think Marjana needs a buff…I mean she is good enough as she is.
About Kelile I would agree, but I would like to have a comparison of 4* snipers and see if she is really unbalanced
With Withstand, and Revive, I like the longer DOT.
But you are not wrong.
Perhaps “skins” will let you double stack burn DOT like a weaker version of the Bleed DOT from Vampires.