I have 14 YOE and its the opposite. Really brilliant jrs don't have the experience to know the consequences of their designs, they build fast under pressure. They reinvent things that already exist (they don't know because they a Junior).
I worked in the music streaming industry, which involves ingesting 10's of millions of XML files. Absolutely do not use XSLT. Schema changes between different versions of DDEX were a nightmare for all the legacy XSLT we had.