Got any specific citations? His general opinion seems pretty clear, but I would like him going on about some details.
I think I remember him saying that if one would want to design a language, starting with Oberon would be his recommendation. In that regard Go at least does something right.
And it does at least have a specification, too, which is another item that Wirth is pretty adamant about.
I'd pay good money to have him and Meyer argue about design, syntax and semantics.
Easy, compare 1992's Oberon with Oberon-07 revisions from 2011, 2013, 2014, 2015 and 2016.
Each Oberon-07 revision, as mentioned, drops language features.
Also note that as far as I know, he wasn't too keen in the offsprings from Oberon, namely Active Oberon, Oberon.NET, Component Pascal and Zonnon.
Oberon-2 was his last collaborative work in the context of Oberon language family.
And while for me Active Oberon is the best one for systems programming (still in use at ETHZ OS classes), with support for several low level features that original Oberon requires Assembly, I doubt Wirth would appreciate it, given that it is Modula-3 like in size and features.
Each release of Oberon-07 drops features, it is reduced to a C like with GC, with a single form of loop constructions.