Really, for "One for all", Why don't pre-ban Heimerdinger like Teemo?
Riot if you think that
's mushroom may ruin opposite player's game, then why don't pre-ban
?
Basically,
's turret (Q) just like powerful mushroom. Mushroom won't attacking multiple time, but they ARE. [zombie-brand-clap]
Once more than 3 Heimerdinger in the same lane, even
and
can't stop them to push.

Even if they facing
. once they got
or all in group. I don't think
can defeat them.
For
there's almost no way to lose, or someone is feeding or AFK. So ppl have to ban him, which is wasting an ban choice. 
Really, think about it. [slayer-jinx-unamused]