I have heard a story that the Vilna Gaon was offered torah insights by some sort of divine source, either an angel, a maggid or something else. The story goes that he refused those insights because they did not come through his own efforts. I would like to know from a hashkafik perspective if this is something that would be considered an appropriate response for anyone or only for someone on the spiritual level of the Vilna Gaon.
As stated in the comments, there does not seem to be a known source for that Vilna Gaon story.
But, there is a Sefer called Q&A from Heaven - or שאלות ותשובות מן השמים in the original.
The author - יעקב הלוי ממרויש - was one of the Ba'alei Tosafos, passed away in 1243.
Apparently back then they didn't mind asking for heavenly help in Torah matters.
'אנו עמלים ומקבלים שכר' - A mitzva is worth proportionately more according to the effort invested. Therefore, the Vilna Gaon preferred to learn the Torah himself rather than learn it through the Divine assistance (or Maggid, as it was known to the Beis Yosef. See writings of R' Moshe Kordevero about Ruach Hakodesh who explains in detail the exact definition of this Malach).
This would be an appropriate response for anybody who had the capacity to acheieve the same status without assistance. Somebody like the Vilna Gaon, who indeed knew כל התורה כולה, could reject the offer on the basis of being able to achieve the same thing with his own effort, rather than being gifted. However, any of us, who cannot hope to complete the Torah without Divine Revelation, would be required (under the commandment of ידיעת התורה) to accept the offer.