My suggestion for banners:
1. Active skills for banners. You drop a banner and you get to activate a active skill for it. Like minion skills for Necromancer or Spirit weapons for Guardians.
Banner of Defense: Staggering Baner
Banner of Discipline: “Furious Rally”: http://wiki.guildwars2.com/wiki/Furious_Rally
Banner of Strength: Brutal Banner
Banner of Tactics: Compassionate Banner
If the active skills are used, the banner skill is used.
This suggestion gives Banners more depth than being a passive summon that increase stats.
2. Traits.
Inspiring Commander: Banner Regens and Shouts heal. Merge the two grandmaster traits together.
New trait: Intimidating Commander: Banner and Shouts damages.
Shouts become a ranged instant burst damage. If an enemy is running away with low hp left, pop all three shouts to make him die.
Banners are a pressure weapon. It deals low damage to enemies nearby. It works the same way how Destruction works. Of course, invulnerable continuous damage is overpowered no matter how small. So the way that Banner works is that an ally must be nearby the banner in order for the banner to do damage. If a warrior drops a banner on a spot and no ally is nearby. The enemy can cap the point without being in combat.
Conclusion: With two grandmaster traits merge together, Tactic warriors aren’t stuck with a kittenty banner or a kittenty shout build. They can build a hybrid.
Go all three banners and place a banner in all three locations? Build two banners and a shout to fortify the major locations? Or build 1 banner just for mid?
5x Warrior, 5x Ranger, 4x Elementalist, 4x Engineer,
4x Necromancer, 3x Mesmer, 4x Guardian, 4x Thief, 4 Revenant