When people are writing the notes section and trying to convince people to vote for their idea, would you all please include an argument for why your new slot idea would be worth the cost (coding and losing a general permanent slot). I personally only vote based on the gameplay merit of suggestions.
I personally find it rather difficult to justify having a new slot in any case. The problems are:
1) The only mechanical reason slots differ from permanents in any case is that you can only have one shield / weapon at a time, thus limiting the potential power of any single card through loss of card advantage. This also means you don't have any reason NOT to have a single shield or weapon in your deck. Having a new slot would mean having a new strong card set, forcing the metagame into losing one or more card slots in their decks to benefit from the new slot. As such, only novelty card slots are any good in my opinion: having a slot that restricts the deckbuilding options and overall strengthens each deck (think of a second weapon slot) is bad.
2) The only flavor benefit of having a new slot is to have a whole 12+ cards serie. This can be easily done including 12+ new cards of a single serie in the game, and doesn't need a new slot at all.
Ergo, I don't think having a new slot is really what EtG needs. I tried to make good card suggestions and have a fun theme alongside them, as that's the best I think we can obtain from this idea. However, that's only an opinion.