Gangplank state?

so after gp was updated he was sharp and you know what to expect from him: sustained early game developing into very good midgame and then snowballing into lategame. right now almost all other champions that are played on top can duel him easily. there migh be some exceptions that gp can beat. well as long as he have mana to do so. othewise these champions just w8 when hge is out of mana and kill him too. so please could someone explain me when to pick gp and why not take other champions

and since gp is in bad spot i made few ideas to make him stronger:

Q: now cost 49 -1 / lvl mana and refunds 5 mana per target killed and has 100% AP ratio when used on minions/non epic monsters and have 20% chance to critically strike.

when purchases upgrades for his r he will get upgrades on other abilities too. 1) Q: on kill grants passive movement speed buff. W:now also removes grievous wounds before heal is aplied E:+5% armor penetration

Q:criticall strike bonus increased by 10%: now 30%+critical strike chance W: aplies passive movement speed buff and refreshes passive E: gp can now store 5 barrels

Q: when Q is not used on barrel gains aditional 20% ad ratio W: heal can now critically strike healing for twice as much scaling with criticall dmg E: when barrel is destroyed by enemy gp gets 50% of cd refunded