Guidance doesn't provide an interesting/meaningful decision point on when to use it (of course, this may not reflect other people's play experience). Other cantrips provide meaningful decision points (Light may give you away to your enemies, cantrips in combat compete for an action with potentially better actions, Shape Water provides an interesting creative decision in its application, etc.). If a player is out of combat and not concentrating on anything, there's no real reason (that I can see) to not use Guidance, or at least pre-cast it before a social or stealth situation. That is the problem I see with it; perhaps others don't see it as a problem, and if that is the case, "if it ain't broke don't fix it" is an acceptable answer.
Providing a pseudo-limit to the use of Guidance, while increasing the benefit, provides a meaningful decision point of when to use the spell. This essentially makes the cantrip Working Together but up to a minute in advance, or with less required narrative justification.
Casting Time: 1 action
Components: V, S
Duration: Concentration, up to 1 minute
Classes: Cleric, Druid
You touch one willing creature. Once before the spell ends, the target can roll one ability check with advantage. The spell then ends. The target cannot benefit from the effects of Guidance for 1 hour.
Since there is a limit on the "spammability" of the spell, the decision of when to use Guidance requires more evaluation. This means I, as a player, have to decide whether to use this on the rogue as they sneak ahead into the room, or save it so I can cast it in advance when they have to bluff their way past the guards in the other room. The potentially stronger benefit (advantage vs 1d4) would seek to offset the usage limitation, and still make the cantrip worth a cantrip slot.
This doesn't stack with Working Together, which is a net loss on many checks. I still think there is utility in situations where Working Together isn't possible (due to the nature of the check or the situation) that may offset this loss though.
My primary concern is that this would obsolete the cantrip since it doesn't stack with Working Together. I think that this could be offset by allowing attack rolls and saving throws to benefit from the spell, making it a slightly more versatile Assist action (caster doesn't have to be within 5ft of the target like Assist). However, I kept it to just ability checks for starters so that it has minimal changes from the original cantrip.