In as simple a word, No.
The plan, however, is to give the user the option to choose default of pigz/gzip or zstd, but PartImage will not have any “default” usage medium. This is because PartImage has not seen any developments and still considers NTFS “beta” implementation. While it “works” it’s not actively developed (from what I’ve seen) and has become quite antiquated.
Partclone will, for now, be the “goto” for capturing images. This is regardless of the compression medium as the compression system is totally independent of the partclone process.
I do plan to add the ability to let the user decide the “default” compression type, but as for the “default compression size” I think 6 is still viable. While it’s not the ‘mid level’ for the zstd compression mechanism, trying to “default” compression numbers between multiple compression types would become very messy to manage. The only reason the “default” was added in the past was because it was unsettable at the time and there had only been one compression choice.