This is my only LOL account, ever. I mostly just play ARAM. \
I do not own just "the good champs". In fact I am slowly acquiring ALL champs and I plan to own all champs before the end of the year.
LOL was introduced to me by a friend. I found it long, drawn out and boring...until I started playing ARAM. I love that mode! Its random and fun and fast. Sometimes I have winning streaks and sometimes loosing streaks.
Sometimes I get a champ I am kick ass with and sometimes I get one where I only feed cause I cant play them worth a damn.
I think what you have here is a case where you got your ass kicked by a Yi or a Teemo or something. Its no reason to shut the whole thing down because someone had a strong champ they were good with.
And just because I only mostly play ARAM, my account should be closed? Do you understand how silly that sounds. Really? :/
Get over what ever loss upset you and enjoy the dang mode =)