Is it important to list the merits of a research paper?
Somehow it is common to start an introduction with a general blah-blah, basically saying that a field is important and repeating some popular facts. 

However, in my opinion, the most important thing of the introduction is to say 


what is there,
what is the actual contribution


and said in a precise way, so reader will know if the content is useful for her. And in such a way as "we prove X1 and X2, under the assumption of Y, and conjecture Z" instead of "we investigate X1, X2 and Z".

Of course, giving the general context is extremely important, but not more that saying what's there.

Personally, I wasted a lot of time reading papers whose abstract or introduction left me believing that they solve a general problem, when in fact it was only n=2,3,4 case, or just something tangentially related to my research interests.

There is an incentive to write introduction in a big talk / general blah-blah style (because it sounds serious, because it may bait uninterested readers, etc), but (IMHO) it is very counterproductive, sometimes verging on the edge of scientific dishonesty (i.e. an implicit overclaim).