In theory, its an “objective standard"; in practice, that mrans the highest court hearing the case ultimately decides.

> And why do judges get to opine on it?

Because its a matter of whether a s a matter of law the vedict is justified. (It's also a due process issue and equal protection issue, preventing a party from beinf deprived of property without basis in law or under standards not applied to other similarly situated parties.)

> If the jury shits on your case, it's called nullification

Nullification exists solely in criminal trials, and only in the direction of acquittals. It doesn't apply for criminal convictions or any civil cases result.

> If the jury rakes you over a bed of coals, you have one safety valve in that the judge can tamp down on things to mitigate cruel and otherwise unusual awards as far as I understand it,

Your understanding is incorrect. The protection against cruel and unusual punishments is a protection against the law providing punishments which would meet that standard, whether in general or as specifically applied to you. It is separate and in addition to protection that any detriment the government imposes on you must be both justified by the law and a consistent with its equal application.