Mafia: general discussions.

I saw games where players specifically wrote quests of different sizes.

I agree, but I prefer it when a list of similar options is offered to choose from.

Added 20 minutes later

And then Koshe had a brilliant idea – to give a clue based on the number under which the player registered...

Well, this is only good for one time, but in general, there are many options to choose from, but it's still better to make them all of the same type.
http://mafiaforum.org/index.php?topic=598.0
actors
http://mafiaforum.org/index.php?topic=521.0
songs
http://mafiaforum.org/index.php?topic=515.0
rulers (see the list of participants under the spoiler)
http://mafiaforum.org/index.php?topic=504.0
writers

well, in general, something like that
I'll post examples of hints from these games in the evening