I think my mechanical skill with the champions I play is good but I don't understand all the match-ups that well. Match-up knowledge is really only gained through a large number of games played. For example I play Jarvan IV a lot so my skill with his kit is pretty good. I know his limits and when I can and cannot start a fight or when I can dive and survive. But I don't know his lane match-ups well enough to dominate my lane when I play him top or who/when to gank for my laners as I don't know some of their matchups that well either. I can get a general feel like who has an escape, who has CC, whose lane is pushing, where will the enemy jungler be, etc. but little things like when does a certain champ hit their power spike still escape me especially if I am unfamiliar playing with or against the champion.
So for next season, I think I will just focus on my three best champions, Leona, Jarvan IV and Thresh. Since I already know their kits well, I can focus on understanding the match-ups in the game and hopefully get to Gold in season 5. I still need to find a mid-laner though and an ADC that I can play comfortably so that in those odd cases I get stuck with that role I don't feed and can at least go even in lane.
On an unrelated note, I think I'll start streaming my game nights as some pretty cool/funny things happen. I almost got a hexakill in my last game night (with Yasuo no less) but wasn't streaming/recording it so lost that moment. Similarly there were some funny moments when my friends and I were playing co-op Interstellar Marines against the freaky robots.