While i appreciate Moomoose enthusiasm, i think that there is another reason to limit number of submission, besides quality.
Personally, i like to follow crucible and forge voting, and when there is a new poll i take time to read every card and try to figure out the mechanics and the subtle details that may are non immediate to see, like interactions with other cards, powerful combos, counters, etc...
This kind of analysis requires time, but i'm happy to do this, because i think that voting is important and good cards deserve to be discovered and promoted.
Raising the number of submissions would mean a very long reading time, and a longer time to try to fully understand the real value of a card, so the voting would become more random and guided by gut feelings, rather than analysis.
tl;dr People need time to understand cards, more cards = less understanding.
