If you decide Rakan needs buffs/changes ...
Look at items items first.
The support role is currently a giant "who can use
/
and win lane" mess. This affects Rakan a lot because not only is his laning on the low end, those items are far from optimal on him. He can build them, sure, but at that point you're better of playing a support champion who doesn't have a good portion of his power budget allocated to fat AP ratios.
The AP support items all work great on him and are actually pretty fun to play with. It feels so refreshing as a Support to go "alright I'll start with zeke for armor , then go Abyssal for MR and finish it up with Banshee because I want a safe entrance in the fight".
Sadly, it does feel like I'm hurting my team in the end by not having the Redemption combo. Sure you could change his numbers around, put less in his ratios and more in his base stats and completely remove part of what makes him so unique as a champion, but I feel like that's really not what you want to do with him. (Feel free to change his Q though, God does this ability feel like crap)
But hey, I'd love to hear some feedback on this. I'm far from an expert at either the game or Rakan and I could be wrong or misguided.