Given the solid precedence for this notation, at least in the works by many of those considered the masters of the French-Russian school of orchestration, I think it's hardly necessary to go that far. Presuming that notation is supposed to illustrate the composer's intentions, whether or not a decrescendo is involved doesn't strike me as particularly relevant.
But anyway, since I seem to be in the minority here in accepting this notation as a legitimate, practical and logical means to a particular end, I won't harp on it much further, except to say that the added impractical level of precision that you attribute to this notation seems unnecessary to me. The only implication I see is the release of a note between two beats, or more precisely, after the entrance of a particular note in another voice. I wouldn't consider that absurdly precise.
As for the practices of Beethoven and others, you might very well get the same effect by simplifying the notation to only include full beats, but only at the musician's/conductor's discretion. Rimsky-Korsakov, Tchaikovsky Ravel and others clearly chose to spell it out to prevent any ambiguity. In doing this, they also gave the musicians a helpful clue of any transitions they might be involved with, at least whenever the notation was used exclusively in conjunction with overlaps.