My take on the idea of a new Mary Poppins:
Mixed, but in the end, the comparison comes down to the script.
That is, IF you choose to compare, you are more likely doing so not because of the performances, but because of how the character is written in the script.
The nature of Hollywood and reboots is that even if the character is supposed to be the same, the script is necessarily different. You can't compare Shatner's Kirk to Pine's, because the worlds are different and they take the character, such as it is, into different directions. Unless they actually remade classic series episodes (with minor modifications for the new continuity) with this new film cast, I will never see a need to compare Shatner's and Pine's performances: I will be spending too much time contrasting Kirk and Kirk directly because in this universe, Abrams's Kirk is not MY idea of Roddenberry's Kirk: too much is different and I am not willing to reconcile.
Same with ANY film/series based on the Musketeers: the writer is going to take a subset of Dumas's original, find what they want to emphasize, throw the rest out, then add in stuff that was never in the books (because they all do), and then the characters become molded by what the plot requires. There's no reason to even begin to compare Reed's Athos (1973) with Sutherland's (1993).
Really, only by a pure remake working from an original script (that is, Shakespeare, or Broadway), do the performances actually become comparable.