I agree with both of your ideas guys, but i have to recognize glacius u made a verry good point. I love this randomize numbers idea in nomlist. Then when ppls will yell "vote 444444444" at mic or in chat, it will be a different 4 for all players. It's amazing to avoid (in part) the fagness. And i have to say there is still some chance than ppls force other by telling the name of the map, but it's more difficult than simply scream 44444444444. It's good for me.
The cooldown isn't the problem. And it's moslly useless for normale players working, having a job the week. Because even with cooldown, players vote the same maps once a day at the same hours. The result is : a player, like me, join basically each days and see wester, serpentis, paramina (or minas), and pirate. Times to times boatescape, atix. And that's it.
Anyway, i just say, let's go test your proposition glacius, if you found a plugin like this