So basically recreate an entire language and library ecosystem because there is one feature that is less than ideal? I hope you realize why a better approach may be to reengineer that one component...
"Is it possible that software is not like anything else, that it is meant to be discarded: that the whole point is to see it as a soap bubble?" -- Alan Perlis
There are several things I personally _hate_ about python, but there is a cost-benefit that comes from engineering new things. What new problems are we going to be able to solve by using a new language? If the answer is clear (e.g. imperative programming vs declarative/functional programming let you solve different kind of problems) then it makes sense to do. If certain constructs enable you to completely avoid a recurring mistake (e.g. garbage collection), then it may make sense.
But this?!?!? No man, you don't need a new language to fix this.
Top comment is proposing basically Erlang or an actor model.
As for immutability... well they have to either have it or manage mutable state.
That task of engineering is not something to scoff at and I think building a new language or using an existing language with those ability would help. Erlang is not a number crunching language. But there are others such as Pony.