In fact replicating already existing programs is just a waste of time, in my opinion it is necessary to add what is missing to AROS so as to become autonomous in operations without the need for external OS.
I am not a developer but in my small way I try to give my contribution, now I'm working on Dopus4 where I'm associating to the best tool all the most common files.
Now I have finished the associations to all the text files like PDF, Guide, HTLM, TXT, etcc, then will be associated device libraries and all the system files that have an extension with program "Version", so that with a click you can see the version and other info on the clicked files.
The only problem encountered on Dopus4 "AROS" are the text files without extension, it is solved by removing the protection bit "E" but this is a problem to do it to all files, other solution is to associate "Read" to all files without extension, but this will also show the executables as text and then they will no longer be executable at double click.
Of course it's a kind of bug only for Dopus4 AROS version, other Dopus4 of other OS don't have this problem.