I don't think the length of anime's is a problem personally. Bear in mind it takes a bloody long time to animate an anime, I would guess 20 minutes strikes the right balance between the length of time it takes to make an episode and being too short for the audiences taste.
As for me, I'd like to see a bit more subtly- Too much is explained in many animes through overly drawn out and dramatic speeches and dialogue- A little subtly wouldn't go amiss.
My biggest pet peeve though is intro and outro music of anime's being wildly out of tune with the type of anime it is. There's been too many occasions when an anime episode has ended on a sad or dramatic note only to be immediately accompanied by insanely upbeat music, and likewise anime's ending in a happy, humorous way only to be followed by some ridiculously depressing music.
As for me, I'd like to see a bit more subtly- Too much is explained in many animes through overly drawn out and dramatic speeches and dialogue- A little subtly wouldn't go amiss.
My biggest pet peeve though is intro and outro music of anime's being wildly out of tune with the type of anime it is. There's been too many occasions when an anime episode has ended on a sad or dramatic note only to be immediately accompanied by insanely upbeat music, and likewise anime's ending in a happy, humorous way only to be followed by some ridiculously depressing music.