Mmmmm yess. Standard Bearers are a must. It would also be a great idea to use them for buffs and secondary weapons. Buffs more importantly so. Not to mention a custom texture would be awesome. So each Strike Force could have its own unique identification.
Yes to both standard bearers and personal, backpack-mounted heraldry. 2 very different things, both very iconic part of W40K...and the personal heraldry items are great for cash-shop, because they can be only for vanity, without any bonuses...maybe with custom or guild theme... Standard bearers should give buffs to people around them, so it could be a support class/item unlocked through progression or/and guild rank, NO cash shop related...
Also to note, perhaps there should be a limit on how many. Only 1 Standard per Strike Force, with a limit of 4-5 personal banners as well. Could have both the cash shop/vanity item for visuals, by which texture you have on the Standard/Banner itself. But also have a buff for a small radius around the bearer of some kind of buff. Encourage people to fight close together when the battle gets really tough.
In real, historical battles, the main purpose of standard bearers was to act as a rally. The chaos of battle made hearing orders nearly impossible and in the confusion of melee, units could lose cohesion and become lost from their fellows. Regiments and other army organization levels had banners with recognizable heraldry upon them and the members of the regiment could see the banner and knew that it was where they were supposed to be. Standards had the secondary function of giving the unit pride and a reason to fight, since losing a standard was a grave disgrace for the regiment that lost it, and a great victory for those that captured it. In the game, the banners could serve the same function, as they give significant bonuses to those that are around them and players that want those bonuses will flock to them. Wise commanders can use this to command the bearers, and where the bearers go, the infantry will follow to where they are needed. How this can be realistically implemented might be that the commanders elect one standard bearer per major engagement zone and these standards are viewable from the game map, so people looking for the battle can deploy to the banner. If the standard bearer is killed, however, maybe the standard is dropped as an item you can pick up upon moving over it. If it is captured by a friendly unit, that unit becomes the bearer and the commander can communicate with them directly and they can pass it off to another unit. If it is captured by an enemy, it cannot be redeployed for an hour or so. Just a thought.
The bigger question is why would somebody want to play as a Standard Bearer, as flags tend to only serve as a giant "shoot me!" sign. Unless the Standard Bearer had an Iron Halo or a Rosarius, I don't see them living very long at all until enemy artillery, snipers, or normal armor pops them specifically to stop any buffs they produce, or to simply piss off or rout the squad they're attached to.
Have fun dying then. Unless it's given some serious AOE buffs for surrounding brothers, it really just seems like having a target painted on your chest. At best maybe it might find a use for diversion by drawing the enemy's attention.