There's a Plethora of Adventuring Fellow threads, as well as quite a many few I've added suggestions too. The thing with Adventuring Fellows is that they follow a job "Suggestion" system, So it'd have to be something like.
Assailer - Ranged DD. (RNG)
Sharp Assailer - Ranged DD +1 (Faster Attack Speed, RNG/SAM, high Store TP, etc)
Elementalist - Magical DD
Destructive Elementalist - Magical DD +1 (Lower Recast Timers, Higher Magic Accuracy and Attack)
This covers two Job "Archetypes" That aren't covered already. a MNK or RDM job would be redundant, Since the only unique thing to it would be Focus or Dodge, and for RDM, I guess Phalanx? - But I like the general idea... our NPC could use some more jobs.
--------- That aside.
I Really wish they'd let us equip our NPC's, Not full on Earrings/Rings... But even just "Visible" Slots like a Mannequin would be really nice of them. Make it a quest. Right now, NPC's are drastically underpowered. The fact that they take up a party slot is an insult considering their underwhelming weakness... Even a Fierce Attack with a Great Katana has less DPS Than a Melee SMN using a Fire Staff. Its downright pathetic. That being said, I really want to draw the attention to an idea i had in a previous thread...
Instead of buffing the NPC through allowing us to equip it, How about simply giving us Better Equipment that improves our NPC (Think Hydra Armor)? - Each one attuning to a Certain Job Type for the NPC. It could all be level 95.
Examples: Mage Set.
Fellowship Cap
DEF:30
Fellow: HP+40 MP+40
Cure Potency +4%
Cure Casting Time -4%
Fellowship Saio
DEF:50
Fellow: HP+60 MP+60
Adds "Refresh" Effect
Cure Potency +10%
Healing Magic Skill +10
Fellowship Cuffs
DEF:20
Fellow: HP+20 MP+20
MND+10 INT+10 Haste +5%
Fellowship Slacks
DEF:40
Fellow: MP+100
Cure Potency +6%
Cure Spellcasting Time-6%
Enhancing Magic Duration +10%
Fellowship Clogs
DEF:20
Fellow: HP+100 MND+10
INT+10 Magic Accuracy +25
Occ. Quickens Spell Casting +5%.
"Stalwart Shield" Set
Fellowship Visor
DEF:35
Fellow: VIT+10 Accuracy+10
HP+80 MP+40
Damage Taken -10%
Haste+5%
Fellowship Surcoat
DEF:60
Fellow: STR+20 VIT+20 Accuracy +20 Attack+20
Adds "Regen" Effect
Adds "Refresh" Effect
Enhances the Effects of Protect and Shell
Fellowship Gauntlets
DEF:35
Fellow: HP+80 MP+80
Enhances Shld. Def. Bonus
Cure Potency +15%
Enmity +20
Fellowship Cuisses
DEF:40
Fellow: HP+80 MP+80 STR+10 VIT+10
Damage Taken -10%
Enmity +10
Haste+2%
Fellowship Leggings
DEF:25
Fellow: HP+30 MP+20 VIT+15
Accuracy +10 Damage Taken -5%
Haste +2%
"Fierce Attacker" Set
Fellowship Sallet
DEF:30
Fellow: HP+100 STR+15 DEX+15 Accuracy +15 Attack+15
Haste +4% "Save TP"+20
Fellowship Hauberk
DEF:50
Fellow: Weapon Base Damage +50%
Accuracy +5% Attack+5%
Weaponskill Damage +5%
Fellowship Gloves
DEF:25
Fellow: STR+20 Attack+20
Haste+5%
Triple Attack+5%
Fellowship Hose
DEF:45
Fellow: DEX+20 Accuracy+20
Haste +5%
Double Attack+5%
Fellowship Greaves
DEF:25
Fellow: STR+5 DEX+5 INT+15 MND+15 CHR+15
Haste+3% "Store TP"+20
As with Hydra Armor, Effects are applied if you're wearing the Armor, When you summon your NPC, So you can Mix-and-Match sets, but only 1 set per Summon obviously. Armor does not need to remain equipped for the NPC to get the buff.
*Weapon Base Damage +50% -
I.E, at current time, a NPC's weapon is about as strong as something a real player would be using at level ... 70, Ish. So for example, say their Dagger is base Damage of 30, +50% Damage would boost it to 45, About on par with current daggers. their GK is say, 70, +50% would be 105, Which is lower than most all Level 90+ GK, But still a solid Damage. The reason this is better than say, Straight "Weapon Base Damage +20" would be that for Daggers or h2h, This would be epic, but for GK or GS, it would suck.
So remember, While that sounds powerful, at current, our NPC's base damage is pitiful, saddly pitiful. Our NPC's as a whole are pitiful. The above stats, While seemingly overpowered, Would actually still make them, on Average, Weaker than a Level 80 Player in Full Perle... I think if our NPC should be anything, It should at least be as strong as a level 80 Perle BST...
That being said - The Armor could come from rewards specific to Fellow Events... The suggestion in another thread was Fellow BCNMs. You can purchase these BCNM orbs with Fellowship Points. Level 99 Uncapped battles. 1+NPC v 1. You and your NPC versus a monster. Fun little battles with the Armor as a nice reward. Maybe throw in about 5k Exp for your NPC or something.