IMO, a tiny percentage bump in an already tiny buff, is not interesting, nor a great incentive to aim for 3 seals. (Well, IMO the whole seals game will be wonky anyway until they change Redraw to always pick a different seal card than currently drawn.) So assuming we're stuck with this boring card system ....

At the current loooooong cooldown, I'd say boost Divination to 25%, and allow seals to increase duration, e.g. base 15 sec, 2 different seals +5 sec, 3 different seals +10 sec. It would be nice if people got a little excited when they saw that buff pop up. I've never heard a single comment one way or the other.