For example, is it better to learn the guitar using an all-fourths turning if your goal is more than strumming pop/folk chords on all six strings.
Many professional musicians use this turning and also state they wished they had started learning the guitar using an all fourths tuning , such as Stanley Jordan, Alan Holdsworth (RIP), Alex Hutchings, Tom Quayle, Justin Perdue and Ant Law.
If you ask the question as: "is it better to learn the guitar using an all-fourths turning" I would expect the question to be closed as any answers would be primarily opinion-based. But you could instead ask something like: "what are some comparative advantages and disadvantages to learning the guitar using an all-fourths tuning." This at least offers some hope of reasonably objective answers.
For what it's worth, I think have heard Tom Quayle say that he wished that he would have stuck with the standard guitar tuning from the beginning; that he has to use standard tuning with students, and that tuning in all fourths makes some things unplayable. The symmetry of this tuning seems seductive, but the asymmetry of standard tuning provides more fingering options; for me this is the deciding factor. I am surprised to see Jimmy Bruno on your list.
Most of these types of question are fine, as long as there are some things that someone could write in an answer that wouldn't be entirely personal.
I also don't think it should really make much difference whether someone asks 'which is better', or phrases the question as 'what are the advantages and disadvantages'. If the answer to 'which is better' is "it depends...", then we can simply say so in an answer, and talk about what it depends on (which would mean that the answer would be about advantages and disadvantages anyway). I've mentioned that in Are we, perhaps, voting to close questions a little too enthusiastically due to giving undue weight to certain turns of phrase? - Asking "what is the best..." is very natural language to use in English, and we shouldn't be closing questions purely because they're phrased in that way.
There are a lot of questions in the scope of this site that won't be entirely objective, and that's fine - even since the early days of stack overflow, "good subjective" questions have been encouraged on Stack Exchange.
In real life, a good teacher treats every question as open-ended. He wouldn't consider an 'is it better...?' question to be solely asking for his personal opinion - he might offer it, but would naturally continue into examples and reasons. And it would very likely end up without reaching any firm conclusion.
But the Stack Exchange culture can be very literal. Give someone an excuse to flag your question as 'opinion based' and you'll get closed down. So it's politic to twist the wording in the way @David Bowling suggests in his reply above. You'll still get the opinion and the reasons for it. Just ASK for the reasons.
Obviously, I won't be offering my opinion as to whether this is rather silly or not.
