eou2 dragons are tougher since in eou2 they have a core (with 10,000 hp from what i read) that comes up around when they lose about 1/3 of their health and every turn they do all party elemental attack and at first its not too bad of damage but the more turns it's alive the more damage it does, and it basically becomes another (elemental) torrent every turn, meaning that you need 2 people with the elemental walls to be able to live when the dragon uses their torrent move and the core's. but on the plus side, i noticed that drake's mirror shield is only use in eou2 right after the second ice torrent and never used again (dont take this to heart i only keep getting to about 1/3 of its hp left because fucking wail puts flavio to sleep when i need him to ice wall against core's move so i cant for sure if he ever uses it again, and accelerate has priority over this so in some fights for me it basically becomes a free turn).
and yes drake's fight is the toughest in eou only because of mirror shield but it's easier once you learned the pattern.
and i understand that grindy feel you feel sometimes but even then i feel like the boss fights are great enough to make grinding worth it maybe because getting your ass beat by the boss is a worst feeling then grinding for me. if there's still difficulty in the boss then learn the bosses weaknesses then rest your characters and put skill points into what'll be good in that fight, because it might not be levels but the skills you have (its annoying, even more at higher levels, but it makes such a huge difference i couldn't have done final eou2 story boss fight without doing that).