So what are all the instances that it gets used in the game.
...
Are their any instances that stand out as not right and might be better served with a modifier?
I have doubts since a year ago about advantage/disadvantage being a good rule...
Clearly, it is
easier than stacking modifiers, and it appears to me that the main reason why it was introduced to the game was exactly to replace modifiers, so that people would stop complaining about having to track bonuses from multiple sources, which ones stack and which not, changing every round of combat, keeping tracks of when they expire etc...
This is where advantage/disadvantage works better than circumstance modifiers, but this is also where its benefits end.
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Let's keep in mind that advantage(disadvantage) has the following simple effect:
it improves (decreases) your chance of success at what you can already do.
Circumstance bonus/penalties have the same general effect
plus an additional effect:
they allow you do things you normally can't (or in case of penalty, they prevent you from doing things you normally can).
This is a very important difference! However, which one is better for the game? To be honest, I don't think there is a universal answer! It all depends how you see it... IMHO it's a matter of preferences.
There is also a difference in
magnitude: advantage(disadvantage) always comes in the same magnitude because it doesn't stack, while circumstance modifiers can be anything you want. Which one is better? Once again a matter of preference, if you favor simplicity you don't need fiddly numbers and a fixed "better chance" is enough, if you favor fiddly bits then you need fiddly bits for more variety.
Keep in mind that we don't have to have
3e circumstance modifiers, with all the multitude of "types" for stacking or not stacking. For a more fair comparison,
we should compare advantage/disadvantage against fixed circumstance modifiers (such as e.g. a fixed +3/-3 that never stack with each other). In this case, there is nothing that works in favor of advantage/disadvantage or circumstance modifiers. They would work both well enough, the only (important!!) difference being having or not having the possibility of doing something you normally couldn't (pick your favourite).
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What doesn't sound good to me about advantage/disadvantage is just that it happens
too often in the game.
There are basically two broad methods of getting advantage on something:
1- improvise a description of your PC's actions that impresses as a clever use of the circumstances
2- use a specific ability that by the rules always grants advantage (can be your own PC's ability such as a spell, or a general combat action etc... anything
codified by the RAW as granting advantage)
The danger of 1- is that it can be too easy. The first time you play, Bob has a nice idea of using his shield to reflect the light of the sun against the eyes of an enemy: kewlz!! you deserve advantage! After trying a few more different kewlz ideas, and perhaps sometimes meeting DM's disapproval, Bob resorts to the same "shield reflect trick" because it worked once, so it has to work again, otherwise the DM is not running the game consistently! Now Bob pretends to make it always work, as long as there is a shield in hand and a sun in the sky. The DM has two alternatives: engage in a game of wit against Bob trying to nerf his tactics, or plain anc clear say she is changing the ruling because now it's boring. This is not so nice.
The danger of 2- is that again the game could be literally bloated by stuff granting you advantage/disadvantage, because it is so easy now for a designer who is designing a spell/ability/item/environmental rule, be stuck with "uhm... what should this give?" and think "but of course, let's put advantage/disadvantage somewhere! piece of cake". How many things in the current packet already grant advantage on attack rolls? Wait until the first few splatbooks, and see that number multiply... and since these are given by the RAW, the DM has little to say on this regard. So now the contest becomes for everybody to find ways to grant themselves advantage and ways to grant the opponent disadvantage. If the game ends up having too many cases for these, the most common case could become that they almost always cancel each other out: net results would be quite the same as not having any advantage/disadvantage at all.
I don't think the current situation is that bad, but I'm trying to express my concerns on how the game might develop after a few months of gaming with the same group and a few published splatbooks later. Think of this as some kind of "asymptotic concerns"
At least my feelings are that 1- should be allowed (as a rule of thumb) only in a Basic game where the material for 2- is probably more scarce, and anyway the utmost care should be taken by the DM to require the player to take advantage of very specific and hard-to-repeat circumstances, that strongly depend on what is going on around at a specific time and place,
not granting advantage for an idea that is too much based on the PC alone (such as the reflecting shield example above... it really depends only on the PC to have a shield, the only requirement of being outside during a sunny day is way too weak). Once the game moves from Basic to Standard, the occurrence of method 1- should be as rare as possible. Unfortunately, the occurrence of method 2- is entirely in the hands of the designers.
As a final word, notice that all these problems would be exactly the same if we had circumstance modifiers instead of advantage/disadvantage. Therefore the problem is not in the advantage/disadvantage mechanics itself, but in how it is too frequently applied.
You can't add 3.5 to a roll.
