Many of the questions so far can easily be answered with the same reply of 'Who Cares?'.
Best writing? I don't know. If I read it, and then I want to play it and can, it has good enough writing. Best cover? Seriously? Best interior art? Is this an award ceremony, or an RPG challenge?
This next one is almost intriguing, but only almost.
As I've stated in the past, it is my humble opinion that most RPGs are over-written.
Too many unnecessarily complex rules, too many rules no one will use because they slow down the game, not enough examples of how gameplay works, but tons of uninteresting game fiction. Ugh. Save me.
Asking which games do the most with the least amount of words sounds, to me, like a misunderstanding of how games should be written. The question should be, 'Which RPGs have just the right amount of words?', or 'Which RPGs use an economy of words to achieve the best results?'
I would have to say InSpectres is at the top of that category. Golden Sky Stories, the English translation, is another that uses what I feel are the right amount of words to get its point across, no more, and no less.
I like to think my own game, The Googly Eyed Primetime Puppet Show, does a pretty good job of this, though it is by no means perfect. In fact, it may be a tad underwritten. I hope to do even better with my next product.
That's it. That's all I have to say on the matter.
Can we get an interesting question now please?