Attach units are awful, and have a lot of problems. A few highlights:
- Their gimmick is being usable as units or reusable buffs. However, they're terrible as units, because if they were any good they'd be too powerful as buffs. Therefore, there's no reason to ever use them as units, and their gimmick is meaningless.
- Even if you did use them as units, there's no way to turn them back into reusable buffs afterwards. You're essentially throwing away a (bad) Equipment to get a (much worse) unit. The two "versions" of the card are completely separate.
- When used as reusable buffs, they have no way to retain value between uses (such as Forge for Equipment). Therefore, their reusability is more of a footnote than a serious design trait.
- They have almost no support, and don't sync up particularly well with any other archetype. Regional "target" Champions like Pantheon and Taric have better ways to spend their time, and nothing in Bandle City has much use for them.
- Equipment does basically what they do, but better and faster and with more support. Darkin Equipment does exactly what they do, but significantly better and with more support.
I could go on for a while about speed, unit mana, and the incoherent Fae type, but I won't. Instead, here are two separate attempts to give Attach units more of an identity, using Quick Quill as an example.
Universal Changes
Both versions include two changes, which would apply to all Attach units.
Altered Statlines: All Attach units (in play) now include the line: "While I'm unattached, I have Spirit." This gives them a slightly better statline when used as a unit, rather than an attachment, which makes them a bit more usable without increasing their power as a buff.
Quick Quill being a 2 Mana 2|2 with Quick Attack isn't good, but it's still much more usable as a unit than before, and its value can be shored up with the right support cards (probably Fae-based).
Other Attach units would need a bit more Cost/Stat meddling; Rainbowfish could probably be a 2 Mana 0|1, a 3 Mana 1|1, or a 4 Mana 2|2, for example.
You could do this more bluntly without Spirit, but just changing the stats could be confusing, and god knows there's enough text on these cards already.
Support Attach: All Attach units (in play) now include the line: "Support: Attach me to my supported ally." This gives them an innate way to become an attachment after they've been played as a unit, which reduces the horrible opportunity cost of playing them as a unit and permanently losing access to their reusable buff form. Support is clunky and easily blocked, but it's still an option.
It also slightly takes the edge off the cost and timing issues of Attach units. Right now, if I want to attach a 2 Mana Quick Quill on round 2, I need to have a 1 Mana unit already out. With this change, I can simply play the Quick Quill as a unit on round 2, then keep it alive to attach it to a unit of my choice through Support in a later round.
Version 1: Mysterious Portals, Norra Synergy
The first version also changes the way that Attach units recur. Instead of returning straight to hand, they're shuffled into the top 4 cards of your deck with a Mysterious Portal attached.
This immediately gives Yuumi and her set direct synergy with Norra, which is nice simply from a flavour perspective. More importantly, it gives synergy with the various boon-trigger effects in Bandle City.
It also offsets the repeated cost of replaying your Attach units as reusable buffs. Right now, attaching a Quick Quill to a unit, that unit dying, and you attaching the Quick Quill to another unit occupies 4 unit plays with a mana cost for each. Equipment offsets the cost by a) using spell mana, b) absorbing Forge buffs to become permanently more valuable.
This version instead gives you a new (random) follower to attach the Quick Quill to, at no mana cost and no timing cost. The downside is that it has an unpredictable delay, and will cost you a draw within the next few cards. I think that's worthwhile, considering the other benefits it brings (and the dubious benefits of immediate reusability for Attach units to start with).
To tie in with this dynamic, I've knocked Quick Quill down to a cheaper 1 Mana 0|0 attachment, which makes it 1 Mana 1|1 when in play as a unit. It would also work with the current stats and cost, but less efficiently.
Version 2: Auto-Summoned, Spell Creation
The second version also changes the way that Attach units recur. Instead of returning straight to hand, they're summoned to the field.
This radically changes the cost of reusing your Attach units as buffs, because the only way to reuse them (bar some Recall or auto-attach support cards) is through their new Support function... but since they go into play for free, you can use that Support function for free. If you attach a Quick Quill to a unit, and it dies, you don't need to pay the cost of Quick Quill again; you just need to keep it alive until it can Support an ally.
It also has a little extra synergy with Taric and Lulu, which is an okay side-benefit.
However, this does make Attach units more vulnerable, and slower to re-Attach. They'll be spending a lot more time as units in this version, so they should have.
Therefore, to give the Attach units a little more individual value, and increase synergy with Pantheon (who is, technically, Yuumi's "intended partner" from a mechanical perspective), I've added a new aspect to Attach units, which is that they create an ally-targeting spell.
Quick Quill, for example, creates a very weak buff spell that gives an ally +1|+0, or grants that buff to an attached ally. It's like a more limited, more specific, slower Yordle Squire... but a) it can add permanent value to the Quick Quill (or other Attach units), b) a weak Fated trigger is still a Fated trigger, c) if the Quick Quill's partner dies, and you reattach it, you can get another spell, too.
The Quick Quill example creates a spell when attached, but it could also use other triggers; Yuumi, in particular, probably has her ability change to creating a (self-)buffing spell in hand each round.