A few members have suggested it but the feedback is generally that it's better to have more in the goodybags and not roll it over than to put less in the goodybags and allow rollover.
Personally I'd go for 3 or 6 month gigabags which is a sort of compromise between both methods without the complexity of rollover.
With those goodybags you get unlimited minutes and texts so how can you roll them over? There isn't any point to it?
Are you aware that some of the goodybags are being significantly upgraded on the 11th of July? As follows: