Currently Assault space marines are still very strong and requires a lot of effort to kill a squad or two and is an absolute nightmare in teamgames
Dire avengers and the doctrines were nerfed to the ground because they were "untouchable" yet space marine players have a similar ability with deepstrike + banner
I don't want to see ASM to be nerfed however i'd like the see some tweaks made the some of the spacemarine mechanics
Suggestion one
Remove the shield or limit to tactical marines
or
Make the shield a proximity based as soon as any squad moves away from the drop-pod the shield is lost
Suggestion two
Plant the standard to have a 30 second cooldown (just like how bonesingers were adjusted) as the game starts however can be countered with Emperor's influence doctrine
These are just some of the top of my head suggestion that hopefully would encourage diversity on how games are played