Charts are (IMO) an extremely complex family of objects, and user’s expectations concerning chart styles may be comparably manifold (and diffuse) as their expectations concerning types and features.
I doubt if anybody (anyteam) will start to implement styles for charts. (And I don’t know in what way such styles might be saved to files and integrated with the existing set of StyleFamilies). The recently introduced table styles in Writer also surely don’t meet everything users pleading for them expected.
What you can do yourself: Create some “sheets of samples” containing charts with data ranges and the like just representeed by placeholders, but setting the formats you want to see for titles and legends and “everything”.
If you want to create a chart elswhere in a sheet you may use one of your samples as a kind of template by copying it from the mentioned sample-sheet and pasting it into the target sheet.
If the source sheet was in a different document, the still rather new feature allowing to re-connect pasted charts to data ranges will then help you to get what you want with much less effort and less error-prone with your “harmonized” formats than by creating a chart from scratch using the wizard. If the source was in the same document, it’s even a bit simpler.
