I will place my answers here. 

 :The Politecnico di Milano is now ranked as one of the most outstanding European universities in Engineering, Architecture and Industrial Design, and in many disciplines is regarded as a leading research institution worldwide. 
 This is vague and unsourced, and clearly POV. Citing positions in international graduatories is acceptable, but these claims add no information, and look more like an advertisement brochure than an encyclopedic entry. 
 :: The Politecnico is the largest italian university in Engineering, and therefore one of the largest and most outstanding in Europe. Moreover, institutions traditionally have, in encyclopedias, a vaguely positive POV, as noted before. This is not different. 

 :The Politecnico di Milano Technical University is strongly oriented towards scientific and technological research 
 It is a Polytechnic. What should it be oriented towards? This paragraph is redundant. 
 ::Aw, come on... 

 :There is no transfer whatsoever of laboratory research to students.  
 ::This, as of now, is completely false. 

 :I got a degree in chemical engineering there, 
 :: Years ago. The Politecnico has deeply changed since then. Your opinion is outdated (and irrelevant, anyways) 

 :Research activities take place mainly at the Departments, where they are developed by a large number of research groups. 
 By all means, where else? In the administration building? How large number anyway? Again, redundant. 
 :: It's a way of phrasing. Feel free to rephrase. Don't feel free to delete. 

 :Starting from Giulio Natta, Nobel Prize for Chemistry in 1963, many scientists working at the Politecnico di Milano received awards and recognition by the scientific community. 
 Natta I kept, of course. But what others? Is there a list of peer-reviewed papers available? Cite examples. 
 :: Look for them on search engines, I found between 1000 and 2000 just in the computer science literature which I'm familiar with, with 3 searches. A number of ACM and IEEE fellows are teaching in my department. Not to cite the breakthroughs of professors such as Dadda and Somalvico, again, just in my field. 

 : Illegality of renting conditions: you cannot honestly deny this. I have not seen a legitimate renting contract in all the years I was there. 
 :: I think your renting experience is unencyclopedic. 

 :Incompetence of some professors 
 :: Incompetents exist everywhere. Again, your personal experience is not encyclopedic.  

 : That the Politecnico administration is a pain is a well-known fact.  
 :: I think it's irrelevant. 

 : Student loss: the ~70% figure is a common one for all Italian universities, I am afraid I have no specific data about Politecnico 
 :: Then it doesn't belong here. 

 : Student politics: I cannot understand why this section has been deleted. What is the problem here? 
 :: That it's both outdated and unencyclopedic ?