First, let's clear up one important thing: The "2012" part of "Anime Award 2012"
does not refer to the time limitation of each categories. This is not an Oscar, unless it's explicitly stated, there is no time limitation in nominating.
The year is referring to when the event is held, pretty much the same with the previous Anime award.
Yeah, except most people nominate anime from this year anyway (or anime that are currently airing even though they've started earlier). It's most apparent in "Best Anime Overall" thread. For example Hunter x Hunter 2011 is way worse than 1999 version but because it's new it's one of the most popular series in this plebiscite.
Could I ask what is wrong with that? Some people might nominate newer Anime over the old one in the "Best Anime Overall", since probably newer Anime is more memorable compared to the old one, and I couldn't see anything wrong with that.
Hunter X Hunter 2011 might be worse than Hunter X Hunter 1999, but remember, that's
your personal opinion. We are trying to respect every member who are trying to nominate their favorites here, regardless whether other member think that such Anime might be undeserved to get nominated due to the lack of quality and the like. The best way to introduce your favorite Anime is, like Uriel said, nominate it. Only by such action, people could vote the Anime which you think deserves "Best Anime Overall".