I just started running into this lately as well, and it has to be a recent change because it wasn't happening prior to a week or two ago.
This seems to be happening only in the reviews and armies sections. The forums still have the standard 30-second timer.
If a timer of more than 30 seconds is really needed, please keep it to no more than one minute at the absolute most. Better yet, if it's even possible, would be to base the restrictions on the user - keep the 5 or 10 minute timer for someone that has only a few posts or has only been registered a few days, but then knock it back down to 30 seconds for anyone with more than X-number of posts (100?) or anyone that has been registered more than X-number of days (30?).
A 5 or 10 minute timer is going to do far more to kill discussion and drive people away much quicker than any amount of spam could hope to do.