I agree completely with this. It really would be easier to have specific apps for things like this. With the Dictionary example, if I don't know how exactly to spell a word, it would be much easier to just scroll through an app than it would be to keep typing out guesses and see if I eventually get it right. With the Flight Data example, having a specific app would mean it could potentially send out notifications when flights get delayed. The little things like that would be really helpful, I think.
Plus, I often don't like to ask Siri things vocally during the day, as I share my office with others and that would get annoying and awkward. Even having the option of typing a question and having Siri answer it would be nice.