you should make some changes first blaziken change sky uppercut for hjk an blaze kick for flare blitz,swampert is ok but i beleve torment is better,venusaur change petal dance for giga drain(you can get it for movee tutor from 7th street) venoshock for sludge wave and toxic for sleep powder,aggron is good,about hunchkrow change wind attack for brave bird and foul play for steel wind and last haxorus well we dont have poison jab yet but if we get it change it for iron tail.
some other changes change blaziken hunchkrow and haxorus nature to jolly.
and some other changes you dont need speed ev's on venusaur better hp ev's and for aggron change the def ev's for hp too and for swampert too change speed ev's for hp i say this bc venu and swamp is rly slow no point for speed ev's and aggro already has amazing def stat is better to put ev's on hp
thats what i would change but maybe you dont like my opinion i just say what is the best changes you can make.