[Groxx]

Seeing it in a context without a UI to show you the row and column numbers felt a bit awkward to me too...

... and it made me wonder if some other syntax would work better, which made me think that maybe something like this would work?

    =sum(column | 2+ | above)
         targets whole column "stream"
                  second item and later
                       above this cell
         pipes manipulate the target "stream"

I'm waffling between rx-like and unix-like for terms though. Or something else. But a much more relative-and-whole-sheet-focused language seems like it could be a lot nicer than pinning cell IDs everywhere.