so I've recently picked up GP, and I've won a few games with him. I've experienced heavy criticism about my builds with him the few games of ranked I've played him; however, I've pretty much put my team on my shoulders and carried games. Can anyone give me some insight as to why other summoners are hating on my build?
I've read a bunch of up to date guides and want to know what I am doing wrong.
The first thing I notice is that your build has obvious wasted stats, specifically too much CDR. CRD caps at 40% but you have 20% from Trinity Force, 20% from Frozen Heart, 10% from Spirit Visage, and 10% from Lucidity Boots. Another thing is the lack of consistent damage from crits with that build. Trinity Force no longer gives crit, so you only have 20% crit damage which is very unreliable. GP does very well with a lot of crit or a lot of armor penetration I've seen. He can also build tanky and do less damage but still contribute due to the built in armor pen from his barrels and his ult's damage. First thing I would do is just optimize your build if that's the kind of build you want. Get rid or Lucidity boots and Spirit Visage (Ninja Tabi/Merc Treads for boots and Banshee's Veil/Maw of Malmortius for the MR) if you are going for Frozen Heart, or replace Frozen Heart with something else like Dead Man's Plate or Randuin's Omen. I personally prefer DMP because GP's Q procs the slow from the momentum passive on it. I would suggest looking at the builds of a player named Tobias Fate because he is a very good player that plays a ton of GP.
Hmm there is an established Tankplank build, where your build seems to be going, and theres nothing wrong with that. People are probably only give you flack because they just want you to contribute damage only. However, Tankplank is still very much viable when played correctly.
source: mastery 7 GP and besides jhin, hes all i play
There's not really anything wrong with your build. Even back when I rocked critplank, I grabbed spirit visage somewhere in there. Mortal Reminder is the most controversial thing in there, but only for people who like to lean on the barrels for damage.
You've got nothing to worry about. Don't doubt yourself if you're getting results!
That built relies alot on rng luck due to only 20% crit, and the mortal reminder is not a very good item unless multiple enemies stack realy alot armor because his barrales already have %pen and %pen stacks multiplicatively, so instead of 45%pen, you only gain 27% for the barrels. You also overcap cdr with your normal items and still use cdr boots. Cdr caps at 40%, which you get from triity+FH already in cases you didn't know.
Going more towards bruiser is certainly strong on gp, though many people somehow think he needs to go full damage.
If you want him rather tanky, i'd suggest building him like this: 
with defensive boots based on the opposing setup.
You can replace with 
if you want to get really tanky and 
instead of should work aswell.
if you want more damage, you can replace with 
+
The flat pen items give alot more **reliable **damage compared to IE and have usefull side effects.
If you want to try something wierd, get 
after trinity for suprisingly deadly ults, and the burn effect also proc off your barrels.
You obviously sacrifice overall damage, but a single good ult can win entire teamfights that way, with out the need for you to show uo personal.
