What do you think makes enchanters easy to play?
Their kits are very reliable. They are mostly point and click (with some exceptions like Rakan and Nami) with active effects (Locket, Redemption etc.). You can't really miss with their kits. You can't screw up a Janna E, or a Lulu W with the exception of casting it on the wrong person entirely.
What do you think makes them hard to play?
Probably relying on their team. More specifically the ADC. But then again, the same goes for most support type champions in the game. Or knowing who to shield (which nowadays is probably their carry).
What makes enchanters successfull?
The fact that you cannot outplay their kits. They mostly have no dodgable skillshots as mentioned above, and there is no actual counterplay to shields except from destroying them or waiting them out (unlike healing, which has Grievous Wounds). That problem is further exacerbated by the fact that with 45% CDR, a lot of enchanters have near 100% uptime on their shielding abilities (IE Lulu's E has a six second duration, and a 5.5 second cooldown at 45% CDR). It wouldn't be so bad if every enchanter item didn't have CDR on it.
That on top of the fact that enchanters can shield an ADC for about half their HP bar with Redemption and Ardent Censer bolstering their shield power.
What makes them unsuccessfull?
The fact that they're usually squishy (aside from Rakan/Taric who both build as enchanter/tank hybrids). They die to the wind blowing through the rift.
What makes enchanters fun to play?
Knowing that no matter what you can have an impact on the game (IE Redemption working while you're dead), or the fact that your powerful abilities,
What makes them unfun to play?
The lack of skill expression. All you do is press your buttons and things happen (with the exception of some obviously).
I wouldn't mind it if enchanters became more like Rakan. His healing is conditional (it's a skillshot), and using his E aggressively can put you in danger. The only gripe I have against Rakan (as someone who plays him), is how reliable his ult into W is.
Or even Taric. His healing is dependant on him interacting with his opponent or his surroundings, and his powerful ultimate has a significant delay and requires coordination to use it at the most optimal moment while providing ample counterplay to his opponents.
What makes enchanters fun to play against?
The fact that a single step makes the difference between them dying and living.
What makes them unfun to play against?
The lack of interaction and the lack of outplay potential. Take Janna for instance. In lane, all she'd do is max W, and press it on you off cooldown while AAing you with her passive, shielding herself to avoid taking damage back and constantly poking you out with Aery. Or she plays meekly and just E's her carry from a mile away. There is nothing you can do about it apart from not being in her range. The same goes for champions like Sona.
Not to mention the fact that they can shut down and negate champion damage with a single button press and there is usually nothing you can do about it.