I decided to hook my 3DS to a Homepass server notebook in order to get some Pokemon dumps, so I made 50 Wonder Trades making notes on every of them, as shown here.
https://docs.google.com/spreadsheet/ccc?key=0AhqEC-9nZNO9dEJRa3NxbTRwWDJKWUlpRVBSWEgzWmc&usp=sharing
I attached BIN files as well so you could verify and investigate if you want, anyway about the numbers:
Though it was afternoon when I started, I didn't trade with any Spanish or Italian guy!
People who Wonder Trade usually (In 50% of cases!) send their bred Pokemon, often with Egg Moves.
Usually people tend to breed starters, out of which Charmander is a total leader.
When you're starting the game, it's worth to Wonder Trade and get foreign Level 1 Pokemon just because exp is 1.5x bigger and Pokemon can have some Egg Moves.

tl;dr Wonder Trade is awesome what do you think about the chart?

Pikaedit XY can open them.
I already tried looking into these stats.