I'm having a blast with my first time playing DAO, and I can't help noticing that Alistair and Cullen have a similar kind of appeal.
You know, handsome but sexually naive templar. What does set them apart is that Cullen is a more mature guy.
You know before playing DAI, I feared that Cullen might be too much like Alistair, but in fact they are quite different. Of course they kept the best part (to me), the naive/romantic/virgin templars style, but as you say their temper is different, Alistair is a bit immature, makes a lot of jokes to avoid the serious questions... Doesn't like responsabilities... He was cute and funny. But I wouldn't say sexy or especially manly. On the contrary Cullen is definitly mature, manly, sexy, a lot more serious too. Maybe we gamers got older as well and would now prefer more mature guys

I loved the romance with Alistair, but I know I would fall for Cullen *_*