Chaosmancer
Legend
Leaving aside my views on the archery fighting style, the key difference here for me is that those are happening during combat, where every character is going to acting in differing ways and with differing abilities, and having to make choices based on position, type of enemies, environment, and etc. And if an entire party chooses to be fighters, rangers, and paladins with shields, then there are a myriad of things that they will face that will not be aided by those shields.
Conversely, guidance's main usage is outside of combat, where it can very often be employed sequentially, without consideration, and continually. "But being support means I can't do other things" doesn't often apply out of combat except in unusual circumstances; in fact you can even cast guidance (it lasts a minute), and then use the help action for a double bonus to the aided character. Or you can cast guidance on another character then go off to climb a rope, talk to someone, pick a lock, or eat some bread.
Hey, I'm all for additional meaningful support choices being available to many classes -- that would be great! 4e as an example included support for supporting for many classes. But for me, Guidance 2014 as written doesn't function in game as meaningful choice of support.
So is the solution to nerf out of combat support into the ground, or is it to offer more types of things we can do out of combat to contribute?
I think what you are noticing is the fact that there is only a single system in place for every single thing out of combat. Roll a d20 and add modifiers. Nothing else matters, nothing else is tracked, unlike combat where there are multiple types of dice and multiple factors to success. And when you have a very simple system, anything that can be leveraged to aid that system is very simple as well.
If we are dead set on not wanting a +modifer to skill checks at-will, the only other thing would be to give advantage. Those are the only two factors to skill checks. Modifier and the d20. But I don't think it is realistic to propose overhauling the entire skill system into something more complex that can handle multiple different types of bonuses. I think that is too ambitious, but I also don't want to see out-of-combat support not exist.