MetaOCaml got backquote and comma? Wow. 😉
MetaOCaml is sure no Lisp.
Lisp without symbols? No way. No late binding? No dynamic features? No, not really.
Smalltalk 80 is no Lisp in a narrow sense, but it comes very close. But that is not surprising, since Kay and others learned from Lisp and Lisp developers also learned from Smalltalk. InterLisp-D and Smalltalk 80 were developed at the same time next to each other. If there is one system that is like Smalltalk 80, it is InterLisp-D.
I don’t think the essence of Lisp is that fuzzy that it is meaningless. Some feature set has been found almost 50 years ago. Some facilities have been added over the years. If you look at trends, I think it is observable that some new languages have a large amount of similar features which Lisp had for most of the last 50 years. There are also crucial Lisp features like symbolic expressions, runtime safety (without that interactive programming is no fun), program generation, reflection, introspection, garbage collection, interactive development that have been (partly) added to language families that have a distinct non-Lisp look and feel.
I don’t think that other languages will morph over time into Lisp, but there are sure more features to be added to some of those languages – features that are thought as common in Lisp. Also there is some trend to more usage of dynamic languages.