Hi, been playing Warrior since launch, my first build was literally banner warrior.
The current change is just silly, it makes no sense to me. While I much prefer the last iteration of banners (picking them up to reduce cooldown by 40s), if you are to bring back pickable banners, why not bring back the old banner skills? And hence my suggestion and why I think it's silly this wasn't at least used in the first place.
You can find the old banner skills here: https://wiki.guildwars2.com/wiki/Banner
Banner skills had 4 interesting component. Each banner would get a unique ability based on their banner. For instance, Banner of Strength would give you an ability to hit a foe and inflict vulnerability. You would get a free charge, which was neat as an additional gap closer. You would get a generic AoE swiftness. Finally, while banners you could drop banner by just switching weapon, you could also use "Plant Standard" which took one second to cast and triggered Combo: Blast. IIRC, the cooldown for each slot was shared across all banners. So if you picked a Banner of Defense and used plant banner, you couldn't pick up a Banner of Discipline and then plant banner right away.
My solution: Bring these skills back, add Quickness buff to Plant Standard, make plant banner 20s cooldown instead. Give back a bit of flavour to banner warrior, more utility and fun in general, might not be competitive, but grabbing a banner to give AoE fury to then charge an enemy and then plant inside an area for AoE effect and quickness would be dank.