I still don't think the Feat sucks, but I do think you need to play a certain type of wizard to benefit from it much at all. We have a Tome of Readiness Wizard (well, it's his second implement) who has the feat, and Improved Tome of Readiness. He also has a Foe Stone.
Thus, he is able to swap out attack spells "on the fly" as it were, and can also find out any vulnerabilities that a particular monster has. By having a broader choice of damage types and conditions, an ability to swap them on occasion, and the knowledge of when to do so, he seems pretty useful.
However, I do think the feat could be more useful in general, without anyone complaining. Furthermore, since you have more attack powers, you also get a little less practice with any particular one, so it doesn't even help as much in this 'edge case'. I still don't think it sucks, per se, but it is definitely 'second tier'.