Anyone else feels like Jayce could use some work?

Look at other champions with two forms.

: Is required to land a Q (or have an enemy step on your trap) to take full advantage of her melee form.

: Must cast spells to prepare spiders for maximum damage in melee form, and pretty much requires to land a stun to initiate properly.

: Ranged and melee form abilities have shared cooldown, transformation is predictable and uncontrollable.

Meanwhile...

: Can switch stances at his leasure, and actually gains buffs for switching stances.

See the pattern? Jayce is the only one that doesn't have to preemptively set up anything to receive benefit from his full combo.

I propose a few ideas for him:

Solution A: Increase the mana costs of his abilities in cannon form, but increase the mana refund on his W while in hammer form. Force him to take some risk and go into melee form so he can use his abilities. Change his damage on Shock Blast to 120% Total AD instead of Bonus AD ( and shave 60 base damage to compensate) so the ability will hit harder lategame.

Solution B: His abilities now share a cooldown, but he gains bonus armor and MR while in hammer stance. Casting a spell grants him a stack of Hextech Capacitor, up to 5. Switching from one form to the other reduces the remaining cooldown on his abilities by 20% per stacks of Hextech Capacitor (up to 100% refund)

Solution C: Hitting an enemy with Shock Blast grounds them, slowing them for 10%. If Shock Blast went through an acceleration gate and hits an enemy champion, every champions within a large radius (bigger than the damage zone) will be grounded, slowing them for 20%. Hitting a grounded enemy with an ability while in hammer stance comsumes the grounding effect, dealing additionnal damage and stunning them, and then chaining to other nearby grounded enemies for the same effect. But the base damage of hammer abilities are reduced. Pros: Stronger combos when landing a Q, plus teamfight utility with potential AoE stun. Cons: Melee form is weaker by itself, although still good for peeling.