However, a comment by the OP stating that they didn't solve his/her
problem caused the downvotes.
This isn't necessarily the case; most people, I find, vote on their own, without reference the whether the OP believes it is correct; especially when the question is unclear.
If the question doesn't provide enough information (not because of
being low-quality) to immediately pinpoint the problem, but a user is
aware of one possible answer (based on say personal experience or
docs), should this possible solution be considered a valid answer
(even-though it may not solve OP's issues) or is it more of a comment?
If there is not enough information, comment. Ask for the relevant information. If you take a stab at it you may well be correct and you may get upvotes but it doesn't necessarily help the OP and it won't help future visitors if the question is unclear.
One more point; "personal experience" is not necessarily the best way to go. Your experience will help you to quickly pinpoint a problem and to come up with novel solutions to one. It is not a substitute for proof. You should be able to objectively prove that your answer is correct, with code and preferably reference to documentation.
Should we post the answer, hoping that we won't get flamed or should
we just move on?
It's the risk you take. You may get flamed in which case just soak it up; downvotes are a lower cost than upvotes. You may not get flamed, in which case you may gain some rep. My own personal preference it to ensure that the question is answerable before answering. If you don't have a lot of upvoted answers it's definitely best to move on as too many downvotes/deleted answers could produce an answer ban.
To a certain extent the length of your suggestion makes a big difference. If it is short then it should definitely be a comment. If you're going into detail then it makes it more likely that you can post it as an answer and "get away with it".