What are some current debates in metaphysics today? I would be very interested to hear what the very most recent debates in this field focus on, what's hot, or whether some new views have emerged or a paper which stirred some things up?
What's hot in Metaphysics? It depends where you look.
The problem of consciousness would be the obvious dish-of-the-day in professional philosophy. As for the rest, the problems of metaphysics are all ancient and nothing is ever 'hot' or 'cold'.
In our universities metaphysics is a dead science and never hot. Indeed, it is so cold that departments are closing. The hot issue would be whether there is any point in keeping them open and it is a widely debated one at this time. Elsewhere the hot issues are the same as ever; origins, freewill, consciousness, space-time, ethics and so forth.
These ought to be hot issues but the professors seem have given up on them. The hot issue might be whether they are right to do this or are being dense. I'll withhold my opinion for the sake of not causing trouble.
If you're asking the question in order to zero in on a problem that's hot in order to study it then for me the hottest issue would be the question of why so many professors believe that the metaphysics of Buddhism is incorrect and in what way. This really does deserve an answer and it's been a long time coming. I believe this will become a hotter and hotter issue over then next couple of decades.
If you want to confirm the death of academic metaphysics you could have a look at the Blackwell Guide to Metaphysics, or better still the astonishing online essay by David Chalmers on 'Why There is no Progress in Philosophy'. If you want see how it looks when it is free from rigour mortis then you could check out Bradley's Appearance and Reality, GS Brown's Laws of Form or Nagarjuna's Fundamental Wisdom.