Vivaro, what could be broken in the near future

Hello. I have already read through various VivaroThreads, but always find only the same or generally little experience. In advance: I do not drive Viraro, I ask the question only for an acquaintance who bought one. Nevertheless, that the car all talked him out, among other things because the part is in my opinion completely wrong in design terms, he bought it through a cheap offer, and thus gave the VW T4 and Ford Transit no chance (yes, Fi The good guy (my friend) is a taxi driver, and drives about 120-150000km a year. The Vivaro he bought is BJ 06, has about 20,000km on it. What do you think that could/will break in the near future? What is definitely broken (some childhood diseases, known defects?) I thank you (btw: pity that there are no usable transporters a ́la transit or T4 from Japan )