I would delve past the word nuanced, to the quality of subtlety.
A nuanced thesis, argument, or debate of any kind possesses "subtle distinction or variation" in its details, borrowing the first sense described by Merriam-Webster.
Then I would turn to the second sense of subtle: "having or marked by keen insight and ability to penetrate deeply and thoroughly [Example: a subtle scholar]", by Merriam-Webster again; emphasis added at "deeply and thoroughly".
This means that you should avoid a superficial treatment of the topic, and do not over-simplify or choose between false dichotomies. In that linked Wikipedia article, heed the advice that there "may be a position that is between two extremes (such as when there are shades of grey)" — nuances, in other words — or consider a completely different and novel alternative, and be prepared to answer the most serious counter-arguments of more than one viewpoint.
A nuanced thesis acknowledges all the complexities and shades of meaning present to the topic. Any solution or answer you develop may create unintended consequences and new problems, and a nuanced thinker tries to anticipate those and adequately address them.
Remember, the ACT rubric also calls for precision of thought, so the writer must aim to sift through all those subtle differences (discerning what is central and what is peripheral), finally reaching a conclusion which answers at least part of a question or conflict.
I've read theses which attached caveats to their findings, admitting how their conclusion may not be broadly applicable in other situations. Some also acknowledge lingering questions which require further inquiry or discussion, outside the scope of your original thesis and so to be taken up in a separate work or by another writer/researcher.
"Second eleven" would never be used outside a sports context - except as a metaphor, in which case it is common. A school, or club, or other sporting organisation, will have a First Eleven in a sport, who are the best team they can field. They will also have a Second Eleven, who are just as keen but less skilled, and possibly a Third and Fourth Eleven. ('Eleven' has no mystic significance, but as it applies in football and cricket as well as other less-known sports, it is often used to generalise. The company's First Eleven would be the best employees they can provide in the field under discussion, who are as likely to be contract negotiators as the literal footballers; the company's First Fifteen in either England or France would probably be rugby players, which makes it a less understandable metaphor.)
So second eleven as an adjective means 'not up to the standards of the best available'. There may be a further nuance, in that the Second Eleven (in sports) is often where you find those who have mastered the physical skills necessary but not fully understood the tactics of the game, which would suit your context; but I wouldn't say that's widely applicable, let alone universally agreed.
Best Answer
When applied to a person, it means the person lacks the ability to distinguish nuance (and thus make good judgements). If applied to the views, the views indicate the person's lack of ability to distinguish nuance.
It may be stretching the dictionary definition to apply it to people and views rather than the quality itself, but that's how it is used.