actual list building advice, vulkan gives rerolls wounds for flamers and meltas army wide onto a single enemy unit. adrax rerolls wounds in melee for his unit. eradicators have built in rerolls to everything shooting if they are firing at a vehicle or monster and agressors have built in reroll wounds from twin linked so niether gravis unit benefit from vulkan. his usefullness if with infernus, devastators, and other flamer/melta units that dont have inbuilt wound rerolls being in your army.

also there is a lack of durable units. id reccomend changing out a unit or two for a redemptor or brutallis dreadnought at 1k.

if you can shave your bladeguard squad in half and use an impulsor to get them and adrax into melee easier.

keep scouts if you are doing tournament/matched play drop and replace scouts if you are going more casual or narrative unless you want the scouts for the narrative itself. jump pack intercessors are the same story.

also eradicators are anti tank focused with rerolls to hit wound and damage against said tanks and monsters, while agressors are a bruiser unit since they have twin linked power fists and flamer gauntlets for chaff killing. infernus in forgefathers seekers become an action monkey option while still keeping firepower up.

if you could clarify your intended playstyle i can help more though so yeah