Over 90% of the 30+ RF lenses released thus far are direct or improved upon replacements of the last EF L lenses.
I suppose it depends on what you consider direct/improved, but I believe that <75% of the 30 RF lenses released thus far are direct replacements or improved versions of EF lenses. (I presume you are not talking about just EF L lenses, because there are only 17 RF L lenses.)
The 5.2mm dual fisheye, the 28-70/2, the 600/11 and 800/11 I'd call 'new'. The 15-30 is the first ever non-L FF UWA zoom, the 100-400 non-L may be a substitute for the 70-300 non-L but it's a significant non-overlap. The 16/2.8 is also 'new' (I would not consider it an 'improved' version of the elderly 20/2.8). That's 7 lenses out of the 30. It's not 30+, by the way, it's 30 and that includes the two extenders and the two RF-S lenses...and if you're going to include the RF-S lenses in the denominator then the RF-S 18-45 is neither a direct replacement of nor an improvement on the EF-S/M APS-C kit lenses, it is the opposite of an improvement given that it combines the most limiting focal lengths of the 15-45/18-55 ranges). So, that's 8 out of 30 lenses that are not direct replacements or improvements of EF (and EF-S/EF-M) lenses, meaning <75%.
If that ratio holds, there are quite a few legacy EF lenses that will not see an RF version. Personally, I expect the 28-300L to be one of those that isn't replaced. Time will tell.