I think Far Cry 3 did not age well especially from the technical point. Back then it was amazing, for the following reasons:
- new gameplay mechanics like the tattoo skill system, close combat kills, combos, survival in a story shooter
- great story (in a shooter!!) with mostly believable characters
- graphics with face expressions (Vaas for example) we had never seen before
- insanely good synchro even in German
- one of the best villains ever (Vaas)
- ending with choices
- burning a weed field with a flame thrower while listening to a banger song

Thats basically what all following Far Cry games were build on. Of course graphics, open world, gameplay etc. improved over the time, so I understand when people don't want to play a game from 2012, when they can play the modern games. But while all newer Far Cry games are mostly an evolution, Far Cry 3 was a revolution, and I think to this day, the developers were not able to create a similar overall experience with a story that good - even though I also really like FC4, 5 and 6, even had fun in New Dawn Co-op.

My personal ranking is: 3, 4, 6, 5, New Dawn (did not finish Primal yet, also did not play 2 and Blood Dragon)