like mostly, i'm opposing. this has been discussed about 15 yearsago, and my arguments still stand (mainly: consistency with dollar-parsing throughout Pd)
Yes, but there is no consistency either now. So the question would be: is the current inconsistency a productive one (do people benefit from having a 0 there), or would people benefit more from having an inconsistency that provides them with a new useful feature?
I can see the argument (no pun intended, haha) here where $1 $2 (and $0 included) mean very different things in non-messages (patch arguments where $0 is the internal/default argument) vs messages and having $0 resolve in messages as it would in objects could be quite confusing as we're mixing two worlds (and then users would perhaps expect $1 $2 and so on to resolve similarly but they don't). So the matter of consistency would be in message world and non-message world where $0 is just simply out of range in message world (as $100 would be if your incoming list doesn't have 100 atoms).
Note that this opens the can of worms of not only message boxes but also things like [text] where $0 behaves as it does in messages boxes.
For me, I can't count how many times I had to add a [$0], or a pack or some extra workaround before a message so that I could send messages to my variables (I hardly use variables without a $0).
Joao
I do face this too where I use $0 with all my [v]s and [s]s and [r]s and it does get to be a bit tedious BUT I'm not quite sure if mixing the two worlds and their rules are worth it...