to all the ppl suggesting new types: please stop it!
i know it's nice to let our imagination work and all that (in fact, it's one of the reasons why i like pokemon so much, because there's a lot left for our own interpretation and imagination) but honestly we don't even have the entire chart explored and that same chart is already unbalanced enough as it is (i know stealth rock didn't help but it was unbalanced since the beginning).
what i would like to see is an overhaul regarding the effectiveness of at least some of the current types.
we don't need a light type to counter dark, we already have fighting for that purpose.
and light as an element is already covered more than well by fire, psychic and especially electric.
to all the other types suggested, just because you already have niche types which were a bad decision for the most part as shown by their usually "terrible" status, it doesn't mean they should aggravate the problem by intruducing more irrelevant and incoherent stuff to the games.