I agree I daresay there's a point of identifying a great piece of kit and continuing it's use. Most of the Warsaw Pact countries were invaded or allied to Germany, Romania, Hungary etc. so they likely had it as standard kit or at least seen it's versatility.
The swiss army uses a very similar mess kit for very long times.
France developed a rectangular version.
After WW2 the Red Army started to use a 100% copy of the Wehrmacht Mess Kit.
(I think, they simply disassembled a few eastern German factories.)
GDR develloped a cheaper but nearly identic model.
Dutch, Finnish, Austrian Army use the slightly different Bundeswehr mess kit.
That design is develloped to the end in my opinion.
If we count the several nearly identic versions we mentioned here together, I am pretty sure, that this model is the most produced mess kit in the world.
The only option to make it better would be a 100% identic titanium version.