The best route is to have the sergeant red helmet be default, and simply a colour difference. The helmet on the store then will only be red to sergeants - and the white stripe shows on veterans. It will be blue/yellow/green/red/light blue on any other marine which isn't a sergeant. (Or white on apothecary.)
thats too complicated compared to adding it as red. it already changes colours when you go into veteran.
Because canonically, not all space marines can go running around with a red helmet willy-nilly. It's red for Ultramarine sergeants It's red for Imperial fist sergeants And that's it. Blood angels used to have sergeants with blue helmets, but it seems that has changed. Dark angels and space wolves i'm unsure of.
those are blood angels. And yes, the devs should totally make a blood angel space marine nipples and abs chestpiece.
We have squad leaders and a metric shit ton of untapped potential when it comes to squad based game play. The Squad Leader should be acting as a Sergeant with extra perks, cooldown abilities or assets they can trigger to assist the squad as well as being a specific class(Squad Leader). And no guys we wont see fifteen two man squads so everyone can be a squad leader. Use the brain in your head and realize we could have requirements in place like requiring at least 5 players per squad for a Sergeant to be able to spawn and 10 players required in the squad for the Sergeant to gain access the most powerful squad assets, buffs and abilities.
The problem is that that would seriously enhance the pug stomping a premade could do. I would be more for an actual way to build a "leader", for example by making "leader wargear" which would double the effect of banners and stuff like that (but would cost LP to equip).