WALL OF TEXT WARNING
Disclaimer 1: This is less of a straight up suggestion and more of a brainstorm I had. This is my first post on these forums but I took a look around the first page of suggestions and didn't see anything like this; still, I apologize if any of this is commonly repeated that you're sick of. And yes, I fully realize that these types of items would take a lot of balancing work to see what's completely overpowered and what's useless and adjust appropriately. Please don't see this as a "PUT THIS IN THE GAME NAOW!!1!!1!one!!" post, but more of a "wouldn't it be interesting if..." post.
Disclaimer 2: I don't play PvP in spiral knights, and don't really have any interest in it. I don't hate it, and I have nothing against the people who play it; I'm simply admitting now that I only have a vague idea of how PvP works in spiral knights, and thus can't really say how these items would affect PvP one way or another. This brainstorm was about the PvE scene, so if anyone else has any input on what these might do to the PvP scene, please, go ahead.
Now with the disclaimers out of the way, let's begin... So, we've got swords for guys who like to get in close, guns for guys who like to stay away, and bombs for guys who like to spread the pain around. But what about guys who prefer to take a more passive aggressive take? Or like to help out their team? Or simply want to change up their default game play in some interesting way?
The jist of the idea is items that equip to weapon slots that aren't weapons; instead providing unique abilities or bonuses. This idea started with me thinking about what it would be like to have the TF2 medigun in spiral knights, and of course immediately laughing to myself about how ridiculously OP that would be. But of course, my brain then turned around and said "But... How could we make healing balanced in spiral knights?" This train of thought spiraled out of control and eventually ended up with me here, typing this out.
For starters, I ended up thinking of two different types of these items. "Active" support items, and "Passive" support items. Active support items you would have to switch to in order to use, just like a weapon. Passive support items would be on all the time, like trinket items. (In fact maybe they could just be new, unique trinkets? I dunno, I liked the idea of taking up a weapon slot as another balancing factor.) Since these would be items that take up weapon slots, they could of course be heated up and crafted along lines like anything else. But one thing I'm not sure about is the level 5 & 10 bonuses. None of these ideas I've thought of involve charging, (At least, none that I've thought of so far.) so that's out. Either they would have no level 5 & 10 bonuses, or maybe they could have max health bonuses. I say maybe max health bonuses to further the idea of these being support items. These would be small obviously, like +1 health at 5 and +2 health at 10 small, so as to not completely outstrip players with more conventional loadouts.
So what kind of items are we talking about here? Well, let me show the ones I've come up with already.
First off is the healing idea, the emergency medical module. This would be an active support type, that I was thinking would go from 3* to 5*. Description could be along the lines of, "An experimental device made by spiral HQ for the purpose of emergency healing on the battlefield. Unfortunately, it has a long recharge time between uses." In game play, you could switch to this item whereupon it would give a little prompt like when reviving another player about hitting your attack key to heal yourself. If you're standing right next to another player and facing them, the prompt would change to be about healing them instead. So, what's the magical balancing factor I thought of to keep this thing from being abused to hell and back for infinite health? Simple, actually; make it so it can only be used once per floor, and the knight trying to use it has to have been in the floor from the beginning. (As in, actually took the elevator down.) Those two balance factors should stop any attempts to loophole infinite healing from this thing. My current thought is that the 3* would heal the same amount as a T1 health pill, the 4* the same as a T2 health pill, and the 5* the same as a T3 health pill, but I can't say for sure if that would be balanced of course.
Next, was another type of healing idea I had as an alternative to the above; as in, actually a branching crafting path of the above. The emergency revive module, which would either be 4* and 5*, or just 5*. Like the emergency healing module, it'd be an active support type that could only be used once per floor by players that had been there from the start. It would have two key differences however; it couldn't be used on yourself, and it could only be used on downed players. So what would it do? Well, you know how when you revive another player, it takes away half of your health and gives it to them? If you used this item instead, it would still give them half your health, but it wouldn't take it from you. Confused? I'll give a quick example:
Player 1 gets downed by something, so Player 2 runs up to revive him. Player 2 currently has 10 pips of health.
Default revive: Player 1 gets up with 5 pips, and Player 2 now has 5 pips as well.
Item revive: Player 1 gets up with 5 pips, but Player 2 is still at 10 pips.
That's my idea for the 5* version anyway; for the possible 4* version, I was thinking it'd be 1/4 the reviving player's health instead of 1/2. So in the same situation above, if Player 2 had the 4* version, Player 1 would get up with 2.5 pips of health. Or, maybe it still gets the other player up at 1/2, but takes 1/4 of the reviving player's health? (Putting Player 1 at 5 pips and Player 2 at 7.5 pips.) I'm not sure which would be more balanced.
The last active support item I thought up would be a stealth item, going from 3* to 5*. It would simply turn the knight invisible for a time when activated via attack key, making enemies ignore them but making them unable to block or attack during that time, only move; with higher * versions allowing more time invisible before it runs out. I'm not sure if this one should also be one-use-per-floor like the healing items, or simply have a long cooldown time.
Now the first passive support item I thought of; the quick shield deployment module, going from 3* to 5*. Description would be along the lines of, "A spring-loaded mechanism allowing a knight to transfer their shield from their back to their arm almost instantly, thus allowing them to keep it on their back when not in use and protect their blind spot." You know how Darkfang thwackers have shields on their backs all the time? Well tada! Say hello to the player version of that. Basically when not actively using the normal 360 degree block, your shield would instead be on your back providing defense from the rear at all times. Downside, besides using a weapon slot, would be that it still uses your shield health like normal. So if your shield goes down, it's useless until it recharges, and taking hits from the rear until it's in the red then trying to use normal block still has the shield at red. Now you might be wondering what the * upgrading would be for? Well, for increasing how many degrees of your back it covers. My current thought is that the 3* would only protect 90 degress, the 4* about 135 degrees, and the 5* 180 degrees.
The last passive support idea I thought of I'm not entirely sold on myself, so I understand if it's not taken popularly, but here goes; the attack compensation module, going from 3* to 5*. Basically this item would give an damage bonus against certain enemies based on the damage types of your other weapon(s). Specifically, it would give damage bonuses based on what the weapon(s) is weak against; so shadow weapons would get a boost against undead and fiends, pierce against slime and constructs, and elemental against gremlins and beasts. 3* is a low boost, 4* is a medium boost, and 5* is a high boost. The hitch is that I'm not sure what, if anything, it should do for pure normal damage weapons; perhaps an attack speed increase?
Anyway, so that's the brainstorm I had. Looking back up at this monster of text, I completely understand if you TL:DR; the short version is: Weapon slot items that aren't weapons.
The devs already said a long time ago that any form of healing outside of what's already in the game would not be implemented. Just getting that out of the way.
However, the idea in of itself of having things that take up weapon slots but support your teamates is not a bad idea at all. Of course it would depend on what it was and how it was implemented to determine how balanced it is. I can think of many things that can be done with this though.