I'm perfectly fine with a reroll. My first roll had an even lower average than Nac Mac Feegle. I was under the impression that we would follow the rules in the PH for mulligans (I hadn't seen any indications otherwise) so I rerolled. I think there is a good reason for making sure someone has at least one stat as high as 14. If I had been asked to play a character with no score higher than 13, I doubt I would have maintained my interest. I don't need mega stats to play a character and I don't mind having the occasional really low score to go with high ones. But a character with no ability score bonus higher than +1 can be really hard to play. The core rules assume you have at least one bonus of +2 or higher and that is the bare minimum. Most classes rely on at least one ability score being fairly high to be played effectively. I'm not saying it isn't possible, but it should be for a lower-powered game if you do. From what I've heard about the slug-fest that is RttToEE, low-powered it is not. Anyway, just my 2 cents on the matter.