What's the best build for a mounted archer/caster? was closed as Primarily Opinion-Based. It is not. It is something on which experts can vet the quality of a given suggestion and vote accordingly; it is not purely about preference. There are good ways, and bad ways, to accomplish this concept. And, as an expert in the system in question, there are limited enough good ways to do it that Too Broad also does not apply.
This meta question directly addresses, and approves of, questions of this sort. We have numerous successful examples of questions of this form answered well here. Two of the reopen votes (per comments) come from users with substantial experience answering such questions (well, if I do say so myself). Some of the original close votes were put on the question prior to a system tag being added, which was completely correct but not clear or visible once five votes had been accrued. It’s impossible (for me, anyway) to tell when votes came in relative to the system tag being added, but at least 3 were (since the final close reason was Primarily Opinion-Based, not Unclear as a lack of system tag would indicate), and only one of those who voted to close the question has experience with this sort of question.
So this question is to draw attention to this question and spur the reopen votes it deserves.