6* Jessie has had a huge buff since she was originally released in the ascendance tower, it is not so much about her current power rather that her power was increased after her initial release into the game - something we were told could not happen with Leon in the past.
Literally days before, one of the worst generation 2 character was released in Romanov with massive complaints at his power vs. promos and that he was, in fact, worse than a 1.5 year old character in Gen1 Red Gov.
Romanov would not need anywhere near the sort of upgrade that Jessie received - a simple +80-112 damage and changing his rush to 550% and make the second half of his rush actually mean something (anything) fire based. Bewildering Fire
Do you think Romanov, Also, needs a Buff?