Heh, didn't expected people to actually read that long post of mine. Thanks for the suggestions!
Leaving my comfort zone to play other roles is indeed a very good suggestion because that way I extend my comfort zone. I guess that if I'm sucking and people are flaming me for that I should just hit that ignore button and not let their comments get to me. If not mid, I like to play top first, jungle second and AD carry third. I don't like support very much, I don't do bad as support but it's just boring.
@Boomcats: No, no ELO hell, I know there's hidden ELO for normal games but afaik that doesn't make as much difference as it does with ranked games. I'm playing normal games and don't expect to hit ranked till S4 at earliest. Learning a champ or two for every role is what I should definitely do, and preferably champs that can be played mid. I was thinking for top to be Kennen/Vladimir, since they're viable up top and mid. For jungle I'm already good with Nocturne, was thinking to get Diana second. For ad carry there aren't really any viable mid champs for it but I kind of like Ashe and Graves, and for support, well, I own almost all supports so I just pick whatever suits the AD carry most, but I hope to rarely support.
As for my game as Olaf against Irelia, I did searched some video's on youtube right away of how Olaf should be played and how against Irelia. After picking the champ and during loading screen I searched up the common itembuild and the order to pick what skill first every level. I badly wanted to play Vladimir in that match actually but was afraid that people would flame me for counterpicking myself. Though never at that match did my teammates flamed me, guess I got lucky.