1.The Idea:

I recently thought about how very not useful most of the af1 equipment is nowadays when a ls member told me, most of the stats on them were made back in the day when the level cap was still 60 and the idea was to make the job more versatile, counter the weaknesses a job has. Of course, countering a jobs natural weaknesses (just take a look at the drk af1 set) goes along with neglecting the jobs strengths (in case of the chaos set, you get parrying skill, evasion, VIT... but only very little to enhance the drks offense, which is the jobs main purpose.)

I realized that the games progression made these pieces of equipment useless and while I have not played the game from the very beginning, I can imagine that at a lower cap and an earlier period of the game, these adjustments could have had effect, in the example of the af1 drk gear, the dark knight might have had a tool to help his defense with that gear in trade for the offensive gearset he usually wears.

In general one could say that AF1 equipment for the most part enhances different aspects of the job which are aside of the main purpose. Every job has multiple purposes while one is their top trait:
Red Mages are top at enfeebling foes and enhancing comerades, yet their secondary skills include the use of elemental magic and fighting with swords or daggers.
Ninjas are excellent at avoiding to take damage while dealing out considerable amounts themselves, their secondary skills involve the use of ninjutsu from enfeebling to elemental damage and throwing shuriken
Black mages are the number one job at dealing out damage with elemental magic, yet they are able to enfeeble opponents if needed
Dark Knights, as mentioned above, specialize in dealing melee damage while sacrificing their defense, however, SE gave them high VIT and the af1 has several defensive stats, their can use elemental magic and even better dark magic.

I was giving examples for the jobs I played a lot myself and I feel comfortable saying that I understand what they are capable of, but Im sure one could continue with this list going through all jobs, they all have main purposes and several more aspects that might not be used that much but become important under certain circumstances, be it the lack of another job, soloing or fighting monsters that have unique and dangerous traits.

2. The Suggestions:
2.1 Purpose of Artifact equipment:
While af3 equipment was for most parts giving large boosts to a jobs main purposes, af1 and relic gear became even less useless.
My idea is to make af1 and relic equipment useful again and at the same time not have it compete with af3 but make the three types of artifact equipment enhance different aspects of the job. There would be new quests discussed below that make upgrades to af1+2 and relic+2 equipment including the artifact weapon which has long been neglected.

The Artifact weapons I imagine themed like the mythic weapons, rather enhancing aspects, increasing stats than for brute damage dealing, in strength comparable to the lesser empyrean weapon. as such, they should have powerful and unique enhancements, however no own weaponskill and most notably no aftermath effect.

To give an idea about how that could look like, I will go into a few examples, again using the jobs I claim to understand well enough

Ninja:
Skills: damage dealing (speed), evasion, ninjutsu, throwing

af3 gear was heavily leaning towards increasing the ninjas offensive melee potential (except the gloves). Looking at af1, several pieces increase the ninjas ability to fight from distance (gloves, pants while shoes and hat have an AGI boost), some increase the evasion and only very little is done towards melee damage output. Going from there, I would suggest picking a theme for each piece (throwing, evasion, ninjutsu, melee) and increasing its values towards that, making it match af3 in power. Looking at the relic equipment, one can see the same structure througout the set. There aswell I would pick a theme for each piece (that doesnt match the respective piece of af1 or af3) and make it a match for af3 in power.

Anju+2/Zushio+2:
add effect: weakens accuracy / add effect: weakens attack
+ ranged accuracy / + ranged attack
- enmity
Af1+2 equipment:
+ ranged accuracy, + ranged attack, enhances sange (does not consume shadows), + throwing skill, adds recycle, ...

Comment: the katanas are designed, a stronger one mainhand increasing strength, a faster one offhand increasing dexterity, keeping the theme I tried to come up with useful enhancements that fit the same "family" as the attribute.

Red Mage:
Skills: enfeebling, enhancing, elemental magic, meleeing (fencing)

red mage af3 gear gives heavy boosts to enfeebling, magic attack and enhancing, however, each piece follows one of that pattern, they are not mixed up in one piece. My suggestion for af1 would be to make it enhance the red mages melee qualities along with the upgrade of the artifact weapon into the style of a fencer. warlocks gloves+1 are a good example. I realize that some pieces might not fit yet, however, comparing the af3 body and the af1 body, I think the enfeebling skill on af1+2 could be traded for a more melee type enhancement as I think for enfeebling purposes af3+1 and especially af3+2 beats af1+1 so af1+1 which is an example how most af1 gear is rather useless at the current state of the game.

Fencing degen +2:
+ crit rate, + sword skill, + parrying skill, adds counter to composure
Af1+2 equipment:
+ parrying skill, + sword skill, + accuracy, + shield skill, + haste, + fencer, + DEX, enhances enspells (maybe occasionally inflict status buff related to said element, e.g.: enblizzard: occ inflicts paralze) , enhances convert (adds a stoneskin effect, similar to afflatus solace) ...

Comment: I think it is more than justified to give the red mage boosts in melee damage dealing, composure shows very clearly how it works, the red mage increases his soloing potential while getting increased recast timers which is not very beneficial in a group, the melee theme should be according to that way so that the red mage makes a good fighter on his own, versatile in offense and defense as it has always been the red mages best attributes, however in parties the red mage should not compete with other damage dealers, as such, the melee themed set should be oriented the same way composure is. It is clearly a balancing issue, not a problem of the red mage having a useful melee set itself.

Black Mage:
Skills: elemental magic, enfeebling magic, enhancing oneself

The af3 gear for blm blew their damage output through the roof, however looking at af1 equipment we can see enfeebling skill and lots of mp recovery while healing. I would like to see the af1+2 equipment tending more towards increasing the black mages ability to self support himself by adding enfeebling bonuses, enhancing bonuses and augmenting the neglected elemental debuff line

casting wand+2:
+ 100 mp, refresh+1, INT+20, increases enfeebling potency
Af1+2 equipment:
+ INT, + MND, + enfeebling skill, + enhancing skill, + fast cast, + magic accuracy, occasionally maximizes magic accuracy, augments elemental debuffs (maybe: depending on day: inflicts enfeebles (means if the debuff cast matches the element of the day, the enfeeble associated with that element will be inflicted or its potency enhanced like a corsairs quickdraw)

Comment: getting strong boosts in enfeebling magic, the black mage is still clearly inferior to the red mage which has stronger and more equipment, higher base skill and tier II spells.

... continued on post 2/2 ...