How would you balance the granted attacks of a hypothetical warlord class?

Have been homebrewing solutions to martial issues recently, and next up is the warlord style of things. There are a couple of things that often get ignored in these kinds of discussion:

• That granting attacks was an element of many of their powerful abilities, outside of at-will actions it wasn't the whole ability by itself. There's a lot of "just be an order cleric/battlemaster!", but all they can do is have an ally spend a reaction to make one weapon attack. That falls far short of "have two allies clothesline the target, stunning them for a round if they both hit".

• That it wasn't just martials. Even people homebrewing warlords neglect that sorcerers could use spells like acid orb when a warlord granted them a basic attack. No reason to exclude half the party.

So, what solves the two? A warlord's at-will output (in the form of using your action to grant someone else an attack) should only be cantrip level, since they're a support class, which means the obvious answer seems to be to let "make a basic attack" include using a cantrip. But then we come to martials - we don't want them making full powered extra attacks because that's the warlord bringing too much at-will power and not having anything left in the budget for resource costing abilities. So a single attack, but it needs to be about cantrip strength. Which leads us to, I think:

Basic Attack: If a character able to take actions is granted a basic attack, they may make a weapon attack or cast a cantrip that is only capable of targeting one creature. The weapon attack option's damage is unaffected by any bonuses that are only applied once per turn, but increases by 1 at 6th level and 1 every level thereafter.

Have playtested it for a session with my group and it's met with general approval, but that doesn't make it a flawless idea ready to become the cornerstone of a class. Given the parameters I've espoused, can anyone point out improvements or something more fitting?