It's a bit of an odd article because the second part kind of shows why dicts aren't a problem. You basically just need to apply the most old school of OO doctrines: "recipients of messages are responsible for how they interpret them", and that's exactly what the author advocates when he talks about treating dict data akin to data over the wire, which is correct.

If you're programming correctly and take encapsulation seriously, then whatever shape incoming data in a dict has isn't something you should take an issue with, you just need to make sure if what you care about is in it (or not) and handle that within your own context appropriately.

Rich Hickey once gave a talk about something like this talking about maps in Clojure and I think he made the analogy of the DHL truck stopping at your door. You don't care what every package in the truck is, you just care if your package is in there. If some other data changes, which data always does, that's not your concern, you should be decoupled from it. It's just equivalent to how we program networked applications. There are no global semantics or guarantees on the state of data, there can't be because the world isn't in sync or static, there is no global state. There's actually another Hickey-ism along the lines of "program on the inside the same way you program on the outside". Dicts are cool, just make sure that you're always responsible for what you do with one.