https://www.wikidata.org/w/api.php?action=wbgetentities&sites=enwiki|itwiki&titles=London|Berlin&languages=en&props=info
Now this request with 2 sites and 2 titles returns 4 elements, because it searches for

• en:London
• it:London
• en:Berlin
• it:Berlin

And if I list 10 languages and 10 names, it will look for a hundred elements.

It seems to me that the logic in the case where given more than one site and more than one title should be different. There should be a pairs of site+title. Such a request would have been very helpful, but benefit from the myriad of elements is very questionable.