been playing him a lot the last couple days. really powerful, decent early game, good mid game, incredible late game. plus i have fun using him. i'm sure the case can be made with anyone as a whole, but in his particular case i like how you have to manage positioning with your cooldowns, and decide when to use what on your dotted targets.
sorry if this is late news lol. i know i havent been as active lately, been fixing my pc. gonna start recording and streaming on sunday hopefully.
my loadout with him is westernesse (4 slot blue) and seat of seeing (2 slot blue). my first 3 gems are ability cooldown reduction, 3 +24ap gems, and 3 ap penetration gems. it's a 6 slot relic belt but it really works for ori imo. at 14 you have 32% penetration which is actually ok, but with ori specifically i think you could just put all penetration as well and get to 50% (with mithril gems).
what are the situations you find yourself dying in? if you can actually manage positioning like this, if you have your dot ("as it is written) on the enemy guardian as well as soldiers, then you can step up and use your shield on the soldiers to get some extra durability before you go in and try to combo the actual player. little things like that will help you in lane.
if you are dying in team fights, then you just need to stand at better spots and decide when to go in or not. if you know which characters can interrupt you, or are even LOOKING to interrupt you, then you can make a good decision on when to engage. don't feel bad about leaving teammates to die if it looks like a bad fight.
otherwise i guess the only other general tip i can give is decide what your combo is going to be and how much of it is realistic to get. you wont always get to have some max damage rotation and stand there for 5 seconds to do it. so just decide what you can go for, and if it's worth going for at all. im not going to ult under a tower if i have to take 3 or 4 shots from it and risk dying for 1 kill if the game isn't on the line (which is not a common occurance at all).
When I play Ori I use a loadout that has 4 slot utility relic that stuns you instead of dying when you reach 0 hp. Somewhere in my belt I put an ability life steal gem or two so that when I do reach 0 HP, (which is usually when I'm using an ability in a crowd) I can usually nuke a few people with my A + X move, which in turn heals me from 0 HP, and then make a quick get away because the other team thought they killed me. It has a 2 minute cool down, but in conjunction with the right gems, an AP+ relic, and that lucky opportunity to nuke their whole team, you become a beast late game.