You are being naive when thinking that everyone will feel a rush and immediately go to UFOpedia to read articles and see the pictures. This kind of thinking leads to exactly what you wrote - that is wasting of this great Blywulf's material.
The thing is, seeing all the stuff before you actually discover it is like knowing what your christmas presents look like way before they are unwrapped. There's no thrill involved. I'm not saying that looking at static pics is what makes a game fun. I also doubt that checking out the UFOpaedia would be the first thing I'd do after installing UFO:AI. However, those images do contribute to the game's general feel and have an impact on the player's experience. They should be viewed as a reward and that's why I'd like to keep them hidden till they are unlocked through research (along with all the stuff that influences the game directly, like new weapons and gear).
BTW I seriously hope that a complete research tree will not be available
before new research possibilities appear.
I don't perceive the art to be a big reason why research is fun in X-COM, so I can't say I find this much of an argument. It varies between people, I guess.
You're correct. I'm one of those guys who enjoyed both text and pics in X-Com's UFOpaedia. It was like reading a book with cool illustrations.
However, the 23rd time I'm in a project, I really don't care.
Not caring about details after having played the game 23 times is a natural thing. Wouldnt you like to be given eye candies quite often while playing for the first time though? Besides, if you lose interest in the artwork then you surely skip the text as well. It's still not a reason to make stories shorter or research info more vague.