Gosh the username escapes me now, but there is a prolific poster on Enworld who plays 5e and PbtA games and mentioned that if a character rolls well on a non-proficient skill (and possibly succeeds) the GM may ask the player to elaborate on why the character succeeded, which the player can then take on the opportunity to expand on the character's background/experience to justify the good roll.
i.e. character succeeds on a boating check (which he had no business succeeding on) and player explains in his character's youth his beloved grandfather would take him out fishing quite often for several years before one day he passed away rather mysteriously when he never returned from a fishing weekend he had gone off alone.
Now I love the implementation of that idea and you can apply in this INT discussion too.
If say player Jeff comes up with a brilliant idea that his character thinks off, the GM can ask the player if he could justify how his character with an 8 INT came up with that idea by expanding on his background/experience or TIBF's.
Now yes you can argue this isn't in the rules but it makes for a pretty good compromise and the table wins as a result. Hell let the whole table offer input to make sense of the roll.
1. Player does not feel restricted;
2. Character lore expanded on; and
3. GM has more to draw on to challenge and surprise the players.