Because of the extinction of the actual Ruling Family, in circumstances that were never envisioned by the creators of the old house laws, the door is wide open for any and all claimants.
However, as I have said before, those closest in blood to the last Tsar and Alexei, are, in my opinion, the closest and most authoritive claimants.
The late Prince Michael Aandreevich and I both discussed this issue at some length,and although HH Prince Michael was very diplomatic in his responses and comments,I can assure you that most Royal Families in Europe and beyond,and all senior Romanov's today,believe that Princess Maria's claims are inappropriate and almost comical.
However, alot of the senior Romanov's don' want the job, some are not even Russian speakers, and God forbid, some are not even Orthodox.
A shame really.
So, I do reiiterate, the door is wide open,but we do need to remember that it is up to the Russian people and their politicians.