The first problem I have with the question is it doesn't define terms very well. In particular, I consider mechanical life a contradiction in terms on the order of "married bachelor". From a practical point of view, robots are tools and their value is directly proportional to their usefulness to people. People are a totally different class of entity and it doesn't make much sense to compare one to the other. Clear definitions are vital to writing an answerable question.
The second problem, which is related, is that the question seems designed to provoke discussion rather than solve a problem. In particular, you say:
I am looking for arguments that are not obvious like examples above.
If you and I were chatting at a coffee shop, this would be a pretty interesting conversation starter. But questions on Stack Exchange are not intended to start conversations, but to be answered. Take a look at the top artificial intelligence questions. As a rule, they present a well-defined scenario and ask probing questions about it. They also often build off of the work of philosophers. Consider, Could a sentient machine suffer? It references Plato, Hobbes, Locke, More, and Bentham. It's not really necessary for a good question, but it sure helps to build on the shoulders of giants.
As for reopening the question, I'd focus in one one narrow aspect of your original scenario. For instance, I'm curious if anyone has examined what role, if any, reproducibility plays in moral status. Is there a difference between an artificial intelligence that can be perfectly duplicated and one that includes some unreproducible element? Instinctually, I'd say there is, but why?
However, I think you'd probably be better off asking a brand new question with a blank slate for answers. That particular question just has too much history to be productively reopened.