Link-only answers are never fine.
If you need to link to a SuperUser question or answer in order to answer a question, vote or flag to close the question as a duplicate of that question.
If linking to the other question does not provide enough information, but you want to provide the same type of answer to express that it's one possible way of doing that, you could, as you say, reword that answer.
Remember that all contributions to SE are Creative Commons licensed, so it isn't plagiarism to copy and paste an entire answer wholesale, as long as you link to where it originally was.
And remember: if you find questions that have tons of possible answers, and other questions are restricted subsets of that answer, you may want to consider closing or flagging the question as Too Broad. I'm not saying all questions that are a superset of some other question are Too Broad, but in many cases that's how it works out.
The first sentence of this answer still applies regardless of any situation. In every single conceivable case where you might be tempted to post an "answer" on any StackExchange Question & Answer site where the entire contents of that answer is only a link (and perhaps some text that says "One possible way is herehere"), there is some other action that you can take which would be
- Preferable
- Less likely to cause your answer to be deleted and/or downvoted
- More helpful to the user.
To book-end this answer once more:
Link-only answers are never fine.
