Drake & Misandra are similar heroes. Moderate stats and a special with a high potential, but often hard to get maximum use out of it.
Lianna, Obakan & Joon have high attack stat so high board damage even if dead. Only 5* Musashi & 4* Guardian Jackal have higher attack stat among yellow heroes.
Drake blinds up to 3, but it can be low as 1, for 3 turns. Joon’s Blindness is not only the highest in the game ( -40% ) but lasts an insane 6 turns.
I agree about the link.
It also is of limited usefulness for a yellow 5* hero. The elemental link +5 attack/ defense really works better with DOT heroes/ allies for +5% attack ( Gravemaker’s & Natalya ‘s DOT are perfect with this) or attack debuff heroes/ allies for +5% defense ( Gregorion Elemental link + Zeline attack debuff works well here because defense is non-linear so upping green defense and lowering all enemy attack stat are magnified ).
Where yellow tends to Blindness and mana reduction, 5* yellow heroes would benefit more from a healing/ minion Elemental link or increased mana Elemental link.
MY PERSONAL OPINION
Between the two, Joon or Drake, I would level Joon first.
But.
I like healers and many of the 5* healers are yellow. So I would take Joon to 5* 3.70, since he is effective at 5* 3.70 ( see links ), then wait to level Joon to 5* 4.80 until you get a 5* healer of any color.
P.S. I am jealous of your Gravemaker and Obakan.
==Links==