Support items shouldn't give combat stats to allies
Just as an heads-up; Yes while most of it is aimed at the current Ardent Censer (as it's at the moment the only support item that gives combat stats regularly), it uses more the current strength/problems of the item to create arguments why support items shouldn't have combat stats, then exclusively focus on the item itself.
Secondly it focuses mainly on professional/high Elo players which really play according to the Meta and power-picks.
There is a summary on the bottom for anyone that cba to read everything.
The item is niche/useless or broken Ardent Censer was barely used for the majority of this season, but is now considered broken, while the item itself only received a small buff at the start of the season, and a small change somewhere in the middle. But as ADC's got stronger (or their counters weaker) the item has become a must buy for any support that can use it.
Support items that provide combat stats just cannot be balanced as it's always related to the strength of the role it provides stats for. If the role is weakish the item is niche/useless, if the role is strong the item becomes broken/must-have. You could try to nerf/buff the item related to current meta, but if that isn't the definition of a problem item, then I don't know what would be.
Supports are supposed to support their whole team. Combat stats are only useful for damage dealers, and depending on what combat stat it gives, are only useful for a specific damage type (like mages, or AA champions). Supports with a combat stat item really has to follow their combat partner around the whole map, as they are mainly a support for that specific partners role/damage type. They aren't really a support for the whole team, but a main support for one role, and half a support for the other roles.
If combat stat support items are strong it limits viable team comps. Especially if the main role the item provides stats for, is in a great spot/slightly to strong, team comps/picks have to really focus on getting the most out of that role. Just look at the current worlds Meta of Ardent Censer. Every team comp so far has a hyper carry and a support that can reliable use Ardent Censer, as those two are the best ADC and Support types for the extra combat stats of the Ardent Censer.
The rest of the team is mainly their to enable the ADC and trying to shut down the enemy ADC. Tank/engage top/jungler to lock down enemies for the ADC to kill with minimal risk, or providing extra peel/defences for the ADC to survive the enemy. Even most mid picks are focused on the strength of the Ardent Censer, with burst champions focused on bursting down the enemy ADC or support to shut down the enemies Ardent Censer (LB/Syndra/fizz), champions that benefit from Ardent Censer itself (Lucian/Corki a bit) or providing extra defences (Galio).
Team comps and picks are predictable; I haven't seen any pick comps, siege/harass comps, snowball/early game comps, and maybe 1 or 2 somewhat splitpush comps with a TP tank (often being Shen).
Overal it creates very stale, predictable games, that from a personal view get a bit boring. Games heavily focus on getting one specific role ahead, and heavily focused on 2v2 3v3 skirmishes around bot-lane, and late game team fight. Even teams with star-players in top/mid roles focus much more on the bottom lane then they did during the summer split of their respective region.
So what should support items focus on then? Support items should focus on enhancing their kits effectiveness, not providing benefit for a different role. Providing extra healing/shielding for utility supports, providing extra engage options for engage supports, provide extra disengage/peel options for peel champions, etc. Supports should feel impactful on a game with their own kit and strengths.
But more then anything support items shouldn't be exclusively linked to ADC's, but be useful for anybody in your team, and somewhat flexible. You shouldn't feel useless if your ADC turns out to be bad, as your items just doesn't provide much benefit for your fed mid/top laner. Items should provide general benefits useful for everyone, like defensive stats, extra movement speed, healing, etc.
And honestly almost every support item is like this; Knight's vow can be switched from your ADC to somebody ells to provide the extra defences, healing from redemption is useful for everyone, extra shields from support items are useful for everyone. But with Argent censer and to a lesser extend Zeke's Convergence, Riot really seems to want to cement support to their ADC's. which is just the wrong direction.
So shouldn't any support item give combat stats at all? Not entirely, but if it does it should provide extra combat stats in a small period, and preferable something useable by almost everyone in your team, like just extra AD/AP or flat damage. Zeke's Convergence, the second of the two support items that provide combat stats, is a better example of how it should been done (in my opinion). It's extra damage is linked to the ult, and only provides extra damage for a small period. While the item itself seems a bit llacklusterr (I have never seen it yet) and the extra damage it provides is again mainly interesting for the ADC, the concept of providing extra combat stats linked to their ult would be great item for example a blitzcrank support in a pick comp, or for a heavy engage/wombo-combo team comp with an Alistar/Leona/Rakhan. It provides extra stats for a small period, and while it can be quit strong the enemy can play around with disengage champions, and trying to force out enemies ultimate.
TLDR
- Combat stat support items are impossible to balance as they are linked to a different role; If the role is strong, the item is strong, and vica versa
- They are only useful for specific roles (ADC's). If your ADC sucks, the item you bought is pretty much useless.
- If combat stat support items are strong, they 'force' team comps/picks to get the most out of it; Ardent censer with hypercarries as example
- Support items should focus on enchancing the support kit, not somebody ells one.
- If support items has to provide combat stats they should be generic (flat damage/ad/ap) and only be active in a small period, like Zeke's Convergence.