It's all good, mate. Cid has had two buffs already - those being coral sword and aignon esper and card. He was already strong, but they are definitely keeping him at the top of the meta. The lightning elemental class has a high bar to scale because of him :)
I don't see how Dark is OP over Light. Light units are also advantageous over Dark units. Furthermore, I've yet to see any Dark units with the Master Ability which grants the party "+ Dark Attack", so I honestly don't understand why people still dares to say that the current Light elemental isn't OP, with there being top grade Light Tanks, Healers, and DPS.
Probably... In theory, Flag of Wezette VC give evocation gauge boost up to 30, while Yuna's staff give +15 magic attack and +30 summoning gauge. Furthermore, maybe in future some esper (either 3* awaken or new type esper) will have summoning gauge boost.