A 5min time break is not bad, because it pleases almost everybody.
Even us, and i am taking me as example, sometimes feel that 5min is too long, because we are "on fire" and with will to play again fast, but then again, there are some days, when i need to stop to go to the bathroom, to eat something, or even just to smoke a cigar (i can not smoke inside my house due to the fact of having a small baby, so i need to come to the street to smoke it) when i feel 5min break is too short.
With this in mind, i think 5min is just right.
What i think it is not so right, is the time players have to make their decisions/to play, because many players take this to the limit to try to get to the number of players that will receive some kind of prize, and that is annoying (to wait one time, and other, and again, and again, and again.....)
I think 5 secs, and then a 15secs time bank would be enough to those who are REALLY playing.
For those who are playing but needed to went away for a minute, it will not be a big lost. On the other hand, those who make everybody wait again and again, wouldn't have a big incentive to do it, because this kind of aproach would not bring them to anywhere.
Please do apologise my bad English