Effects of awarding extra skill proficiency for high intelligence score

After a discussion in my Pathfinder group about D&D 5e, someone threw the (often heard) complaint that intelligence was mostly a useless stat outside of the classes for whom it is a primary stat. Seeing as the knowledge skills heavily depends on the GM’s style, investigation is, in my experience, usually replaced with perception (again partially the DM’s fault) and added to the fact that there seem to be only a few classes that uses Int for their ability.

We eventually came up with a house-rule suggestion :

  • An Int score of 14 grants an additional skill/tool proficiency.
  • An Int score of 16 grants another proficiency.
  • An Int score of 18 grants double proficiency for a single skill (similar to Expertise)
  • An Int score of 20 grants another double proficiency.

Since none of us have extensive experience with the D&D 5e system, we’re not sure if this rule would break the system at some point. Has anyone used a similar rule or sees a reason this might imbalance the party?