This might be a bit of a long one since there's a few other issues with crafting in general to look at that have cropped up as new additions have been made, namely the conception of Tools and Material Kits making higher levels of certain crafts obsolete (Tailoring being one of them).
I can definitely get behind adding more previously uncraftable items as recipes for Tailoring considering how woefully underpopulated the list is.
Especially when you take into account how many new recipes have been added to other crafting types.
Comparing recipe lists (Tailoring - Metalworking - Wood Working)
Tailoring gets a small handful of weapon components and a few low level torso items. And the recently added Plus items (that are on the more lackluster side of the upgrades)
For a grand total of 16 recipes for the whole craft. 8 Weapon components, 4 Torsos, two Shoe slot items, and one Hand slot item. The only crafts requiring more than one invested point to have a chance to succeed with Cotton are Double String and Wrapped Knuckles at Difficulty 5.
To put it into perspective, I'll layout a few lists of other craft's available recipes. While sheer quantity does not dictate the usefulness of a craft, it's undeniable that while what Tailoring provides is unique it is grossly eclipsed in usefulness by many of the other crafts still, and the same goes for a few other crafts that aren't Metalworking, Alchemy, Enchanting, Tool Creation, and Cooking. Which is basically just Wood Working. So really, most crafts are in a good spot having a relevant niche in the crafting world (Most crafts in the game, Material Kits, Enchanting in general, Quality upgrades, food. just food.) aside from the two black sheep, Tailoring and Wood Working.
Without further ado, Metalworking's terrifying list of recipes.
I may have missed a few but from my count, including the recent Plus items(adding 9 new recipes to it), that brings Metalworking to 138 unique recipes. 61 of which are Weapon Components, accounting for roughly 71% of all the game's Weapon Components.
Lastly, I'll show Wood Working's recipes.
28 total recipes for Wood Working, 12 of which are Weapon Components.
I won't bother laying out the lists of the others, as Tool Creation, Alchemy, Enchanting, and Cooking all have clearly unique recipes with a different purpose entirely--with Enchanting serving the dual purpose of applying enchants to gear. I can also safely say each one has many, many more recipes than either Wood Working or Tailoring. Metalworking was displayed as its the most similar in purpose to the two (creating base gear to be modified/weapon components).
So we have 16 (Tailoring), 28 (Wood Working), then 138 (Metalworking). No guesses as to which craft attracts more people. Especially when you consider that with bare minimum investment, you can still technically make all the parts from Tailoring with one point and Wood Working with two, assuming Legend Ink investments are made, leaving your remaining 4 points to completely max out Metalworking.
With material kits making higher than necessary crafting level obsolete, it's no longer a boon to be able to craft armor/torsos with higher grade materials when an Alchemy spec'd crafter can simply print a kit out
(not to mention this method is essentially mandatory for creating higher difficulty weapons/armors into remains materials). Level 6 is just for 100% success chance on the highest difficulty Weapon Components, Material Kits, Magic Stones, and Quality Tools. The issue being it takes away the impact of hitting 'Great Success' on weapons and armor.
Thus with all this in mind, you can see why Tailoring (and Wood Working to a similar extent) needs to have its repertoire expanded to compete with Big Brother Metalworking. Porting over previously uncraftable items already present in the game is a good start, and for Tailoring this is a staggeringly high number given so many Cloth material items are not presently craftable. This solution wouldn't be as easy for Wood Working given the relative scarcity of wooden equipment outside Bows and a small number of uncraftable Spears.
My own solutions
I'd propose trying to give the three 'base-item' crafters (Metalworking, Tailoring, Wood Working) their own niche to promote specialists in these three just as Tool Creation, Alchemy, Enchanting, and Cooking have carved their own niche in the system.
My own idea for such a system would be something along the lines of unique quality upgrades that apply only to crafts made while at the maximum achievable level (6). Like additional Phys Def or chance to proc Eviter or something. It'd take some thought to iron out. A simpler version of this change could be to have Quality Tools applied by the appropriate craftsmen (I.E. a Metalworker applying tools to a Longsword) having a greater effect.
Another, more simple idea, is allowing higher level crafters to raise the Upgrade Level of items relevant to their craft slightly higher. Not super impactful but still desirable to those wanting to squeeze all the numbers they can get out of their gear, thus creating a demand for the formerly nigh-useless crafters. Sort of. Metalworking would still reign supreme with this method given the amount of Metal items.
Ultimately the issue that needs to be solved is the lack of incentive to be a level 6 (or even 5) Tailor or Wood Worker compared to the far more useful facets you could commit your 7 crafting levels to. A perfect balance is impossible, they just need to have something that's more frequently desired than Wrist Strings and Heavy Arrows to compete with Material Kits and other such coveted consumables. The ideas I've provided are purposefully bare bones as I just want to spark possible avenues to take for poor Tailors and Wood Workers out of the job.
Ushering in more present items into the crafting pools of the lesser used crafts is a step in the right direction, but to remain relevant they'll need to have a niche on par with the present crafting giants(Alchemy/Enchanting/Cooking/Tool Creation) to incentivize players into spending levels raising them rather than ignoring them outright the vast majority of the time, likely in the form of unique consumables or interactions with relevant gear to their profession to creative incentive to commit to the lesser represented crafts.