Replace the named unique attribute buffs that traits and utilities provide for simple, single-attribute improvements provided by these traits, but they no longer stack. these can be stronger than the current ones (since they don't stack) but also get overwritten when group comp is ill considered.
These suggestions would have the most impact on warriors due to how banners work; however I am not a warrior main complaining about my class; I honestly play very little banner warrior because I find it very boring, and that's what I'd like to address. I do play every class throughout Tyria and the Mists, but have spent the majority of my time on Ranger (Druid in Raids), Warrior (SpB in WvW), Guardian (DH/FB in Fractals) and Revenant (Herald in WvW); Thief and Elementalist are my least played classes, while Engineer and Necromancer are primarily used for open world roaming; Mesmer's been played in both PvE and WvW; but I'm avoiding Chrono-jail by constantly remaining at least one meta behind.
I will be limiting my discussion to PvE content (and primarily raids at that) as almost every one of the bonuses I mention below are currently 10-man buffs. I'm not addressing WvW and PvP as there is a skill split; so if any of my suggestions appear outrageously OP in either of those modes, I apologize.
As of right now, the PvE raid situation is pretty much as follows:
I believe these perceived mandatory stat bonuses are hindering the diversity of group comps as well as the diversity of possible situational build diversity (e.g. Bannerslave Warrior, regardless of your build; you are expected to bring banner(s), this is limiting your DPS, CC and other utility options. likewise a Druid is always expected to bring Glyph of Empowerment and Spirits; limiting their personal DPS options).
There are 4 classes that are excluded from being able to provide 10-man buffs in raids.
Thief and Mesmer do not have any 10-man shared Attribute buffs; and I think the elite specializations from Heart of Thorns provide a space for the two stats that came with it: Concentration for Chronomancer, and Expertise for Daredevil.
Summary of my suggested spread of the passive boon traits
Guardian: Strength in Numbers: maybe this trait should function more like Flesh of the Master) to allow a guardian to toughness-tank in a raid while buffing allies with 100 toughness each. (+25 toughness per affected ally; so in 5 man content the Guardian would still have 125 toughness while allies have 100)
There are now a maximum of 9 unique attribute bonuses on your buff bar, instead having 3 for every 2 stats (e.g. Ferocity+Precision=AP+Banner+Spotter) the existing icons could remain in place if you'd like; so that overlapping bonuses end up swapping between the two icons on your bar; making it easier to spot when there's a conflict of duplicate traits/bonuses.
The trait Assassin's Presence provides the buff-bar effect of ++Ferocity (source: RevenantName)
The trait Spotter provides the buff bar effect of ++Precision (source: RangerName)
The Banner of Discipline provides the buff-bar effect of ++Precision (source: WarriorName) ++Ferocity (source: WarriorName)
If multiple of the same buffs are present in the area, they override each-other instead of stacking.
The values of the bonus is subject to the balance teams' discretion; but if say ++Ferocity gets buffed; it gets buffed for both the Banner and Assassin's Presence at the same time; meaning that both options remain valid.
Currently existing and future Elite Specializations can include these same ++Attribute bonuses in their traits; with each of them providing an alternative to the existing trait picks, and each of them can help denote the overall theme of the specialization by providing an offensive, defensive or supportive benefit to your allies. some examples include ++Toughness on Scrappers; ++Vitality on Weaver, ++Concentration on Firebrand.
I assume that some of you may be thinking, these changes would just flat out make banners obsolete; because always-active-traits will be preferred as they cant be failed/forgotten this is not necessarily true for a few reasons; everything is dependent on the balance team though.
1. 1 banner gives 2 benefits; so a warrior with 1 banner provides the same as 2 classes bringing specific traits. This opens up build options for other classes.
2. Banners are stationary; so can be in placed in a spot to benefit as many people as possible; even when the buff providers in the party/squad split up to do a mechanic or split phase.
3. Banners can be traited into, these augmented banners could provide benefits that those passive traits wouldn't give; either boons or a unique buff for the warrior would solve that (detailed below)
Forever returning to Warrior; as it is the most hampered by its unique bonus providing capability through banners: In a power heavy group comp a warrior is expected to bring both Banner of Strength (Power+Condi Dmg) & Discipline (Precision+Ferocity) as well as Empower Allies; this is 3 mandatory slots to provide buffs to their group. Meanwhile the Ranger brings Spotter and a Revenant (might) bring(s) Assassin's Presence;
In my suggested alterations the moment your squad or party has a Ranger & Revenant in it running their appropriate traits; you don't need a warrior to bring the Banner of Discipline; and if they pick the Empower Allies trait, they don't need to bring any banners; giving them 2 utility slots back.
If you've made it to the bottom of this; thanks for reading; I realize this post may have been better suited to be cut into two topics; one regarding Standardizing Unique Buffs and another about Missing Bonus Attributes; but alas; here I am; a few hours into typing all this; unable to go back and split it evenly without fear of repeating myself in both threads.
I look forward to reading your salty responses, and hope we can get some constructive dialogue going non-boon buffs in group content