Rakan being melee would completely screw him.
He is just by design squishy and thus he can't afford to absorb even a pair of hits to get a proc of FoTM for his ADC if it is needed, unlike what the tank support can do (he needs the shield for when he goes in or body block for his ally), and he gets pushed in by heavy poke/harass lane, and in addition to that he can't even reliably kill minions with his Q because of the low damage so FoTM is not useful, and its use shouldn't be pushed
And Coin line is very good overall, it is just that starting Coin item has become even worse because less safer for him as it relies on his ally being able to kill minions at decent rate and his ally could just not do it, he has to hold on and not feed untill he can get Nomad where he can start to fight back consistently...which causes low win rate because if bot lane start to crumble in soloQ it is usually a trouble
To be honest, I think they should partially revert the W and E changes on 7.10
W should get less damage as it is not really the main strength of that spell and should not take more power budget in term of damage than what had on release state, E shiled value should be better at lower levels when Rakan has to keep it up with enemies(either higher base and lower scaling like 70/90/110/130/150, or same base and having it scale a bit better at 50/80/110/140/170 depending on how strong you want his shield to be at late levels)