ばいい
Structure
Verb[ ば ] + いい
Explanation
[Used to ask for/give emphatic advice/express good option. Common phrase: どうすればいい - what should ~ do/how do ~/ how can ~]
[Used to ask for/give emphatic advice/express good option/wishes(often with なあ). Also, can be used together with のに to express an advice/wish that regretfully differs from actual state/is impossible to realize. ]
Is there anything wrong with 出ていくべきなんでしょう rather than 出ていけばいいんでしょう?
It’s the strength of the advice; empathetic suggestion vs. obligation
違いを理解するために、再び文法ポイントの「ばいい」と「べき」を読み直せばいいです。
In order to understand the differences, it would be a good idea to re-read the grammar points for ‘ba ii’ and ‘beki’ again.
違いを理解するために、再び文法ポイントの「ばいい」と「べき」を読み直すべきです。
In order to understand the differences, you should re-read the grammar points for ‘ba ii’ and ‘beki’ again.
I think といいです grammar could work as well with a slightly different nuance as well. Then there is たらいい、てもいい and ほうがいい. I think these get a bit more confusing on nuance compared to above.
Should there be a notation for よい? Came across that while reading Harry Potter. Threw me off for a bit, haha.
What’s the main difference between this and といい and -たらいい?
They seem very similar, but it won’t take them as the right answer for ones where it wants the other one.
@DarkConfidant
Hey 
They are generally interchangeable with small differences being that たらいい feels a bit more casual than といい (and ばいい）and といい cannot be used in questions, while both ばいい and たらいい can, so どうしたらいい and どうすればいい are OK while どうするといい？ is not.
Another thing, when といい is used when giving recommendation/advice it might have a slight nuance of the action advised might generally be recommended thing to do.
Other than that they should be interchangeable (in giving advice (though it adds mentioned nuance), also in all cases where one wishes or wonders with といいんだけど and so on), and if they are not accepted than its an error on our side and I’ll fix it (will check all of the sentences one by one).
I hope it helps,
Cheers