Side comment for emphasis:
Foresight is a 9th level spell - that is, the highest possible echelon of magical casting, that contains spells like meteor swarm and wish. It's available to 17th level pure casters that have dedicated their entire adventuring career to gaining this degree of magical ability.
Foresight's purpose is to give one target free advantage all the time for 8 hours.
At least this is somewhat balanced out with enemies also being able to exploit the same (height only) advantage (oftentimes placed in advantageous tactical positions at the onset of combat, and an AI who prioritizes height advantage literally above all else
).
Alternatively height/flanking advantage is much better than the Barbarian's Reckless Attack - which is a core mechanic of that class. Reckless Attacks gives the Barbarian advantage to all attacks, but enemies likewise get advantage to their attacks vs the Barbarian. This allows the Barbarian to be a DPS machine and tank because it in effect taunts enemies by incentivizing them to attack the Barbarian in preference of more vulnerable party members. Totally broken ability/mechanic by the over-incentivizing of tactical positioning (which I actually do agree should provide a small bonus, ie. +2).
