1st: yes, I'd like to see many concepts implemented, expecially the older ones. There are so many good concepts in the end of the list.
2nd: I have to say that in every update there new cards are like 75% porposed concepts. also some keyword were proposed by the comunity and implemented (aqua, runic, horde, next will be aria). So I think that the comunity have a major role in the game's development.
3rd: There are too many concepts,the implementation of just one card requires so much time that is impossible to add more than 10-20 in an update (there is legend talking about Mojko having a life and even a work).
4th: the voting system works fine with a greater active comunity, as we are now I think that there will be at most 10 players that follow the concept's development and could vote them. also all updates are previewed so that anyone could comment them (it's like a restricted voting system)
5th: too many new cards could ruin the balance of the game