Antag voting (putting the roundtype up to a vote) is an interesting feature some servers have. The general premise is to maximize fun by maximizing the number of people who get to see a roundtype/antags that they like and enjoy on any given round. That sounds pretty reasonable, but there's a few glaring issues with implementing it here:
People with preferences for antags others don't like never get to see their favourite antags, which is no good.
If people vote for the same antag type every round, there'd be less variety and thus arguably less fun.
Players can get metaknowledge of the antag type by looking at the vote stats. Having metaknowledge of the round type takes away from the classic SS13 uncertainty, and ultimately leads to metagaming.
How antag voting could be implemented on paradise:
Antag voting has the potential to improve overall fun for everyone IF it's done right. Instead of a majority vote determining the roundtype, every vote for a roundtype increases the weight of that roundtype. The votes would also be hidden from players, to keep meta at a minimum. Antag votes would be polled on a per-round basis and not picked in the game preferences tab, and would be optional. You'd get a dialog at the start of the round prompting you to pick 1-3 roundtypes you'd like to see this round, for instance, then those choices would be added to the weightings to determine which roundtype gets picked. Ultimately players' preferences shouldn't be everything in determining roundtype; even if EVERYONE voted for blob, there'd still be a 40-50% chance blob wouldn't be picked, generally keeping variety high and metaknowledge low.
Extra - midround polling:
This is slightly harder to get right: Allowing players to influence which major/minor midround events fire. This should probably be restricted to unrespawnable ghosts, that is, ghosts that either:
Have AHud enabled and would like to spectate a particular midround,
Have been removed from the round permanently in some way or another, either through cryo or having their body destroyed,
Have been dead for a particular amount of time, IE bodies thrown into lava or into space or otherwise made unlikely to recover.
Have joined the server in the middle of a round and would like to participate in some way.
Why unrespawnable ghosts only? Because it'd have the potential to promote metaknowledge in the case of a player deliberately dying, voting for a midround, then resurrecting again.
Alternatively: All players could be polled at the START of the round as to which midrounds they'd like to see, with the same system as with roundtype voting.
Being able to influence the roundtype will naturally lead to more players seeing more of the roundtypes and antags they like, and less of the ones they don't like, while still allowing the less popular ones to be rolled for variety's sake and for the sake of the players who do like those antags. Generally, the goal is to have more players having more fun on more rounds, without having to fine tune antag weightings and balance them accordingly to their rarity: The playerbase will pick, in some capacity, what's most fun for them.