You could use the assault doctrine, then switch to a shooting one before all your ranged attackers shoot. It says to change the doctrine so that would be for that operative and all those that have yet to activate or counteract. Pretty useful actually. Could be a lot of rerolls if played right.
I so wanted the heavy gunner to be more viable, his wounds plus heavy bolter is such a fun thematic choice, however, outside building some teams for variety/theme, the sniper does outrate it highly. Just being able to deal with enemies using its optics, rounds with seek light etc mean that it isn't as dependent on vantage to still be a valuable threat. And seeing its utility does often mean your opponent is forced to play around it (be it through avoidance or focusing it as a threat) in either way its not something that can just be ignored making the value in just strategic behavior modulation that much more valuable. Even for a melee focused team, being able to pick off select enemy threats makes it just shy of an auto include where most reasons not to pick it would be to build for a theme. I am happy we do have at least some kind of mix in having a phobos and a gravis option in the squad but I really hope in the future, we get something like a modernized space wolf combined squad or even a black templars crusade squad in the mix. I'd especially love a Crusade squad with maybe at most 3 normal astartes initiates with 3-4 additional neophytes. I'm sure we would need to see how it is ballanced, I think if they were to give these neophytes all the astartes rule, you wouldn't need to push it being a bigger squad, but I could see balance dictating maybe a sergeant, 3 initiates and 4 neophytes if they were needing to use command points to temporarily get the astartes special rule. I think they could get away with giving them all astartes special rule but not giving neophytes the scouts specialist equipment (Ie: limit the equipment choices to boltguns, shotguns or chainsword+bolt pistol on them)
