I was thinking of upgrading my two current Corsair Vengeance 3200Mhz 8GB sticks to two Corsair Dominator Platinum 3200Mhz 16GB sticks. I don't quite know if this is a particularly wise idea. I bought the Vengeance sticks because they were around £100 cheaper than the Dominator sticks a couple of years ago but now I have a bit more money I was thinking of going for the Dominator sticks. I am also aware of the possible release of DDR5 memory soon. Would I be better off waiting for those to release?
No, no editing, only gaming.
For strictly gaming, this would be a completely pointless 'upgrade' IMO.
Monitor RAM usage in-game. If you're not coming close to maxing out 16GB (I'd be surprised if you're using >10GB), then bumping to 32GB will have absolutely no impact to your gaming performance.... and a noticeable hit to your wallet.
As for DDR5, new RAM standards hit servers long before consumer-level hardware (as in, some months as Server 'exclusive', HEDT after that,
then consumer). Likely somewhere in the ballpark of 18 months - 2 years post initial implementation before you see DDR5 on a desktop socket.
As examples:
DDR3, launched in early 2007 and was on a consumer chipset (P35) 2008.
DDR4 as an example, launched in Q2 '14 (server), Haswell-E implemented DDR4 (Sep '14), and Skylake was the first consumer (June-ish '15)
Mid-2020 Epyc releases are still touted to run DDR4, meaning DDR5 is unlikely to be implemented until late 2020, early 2021 at the earliest. Following the DDR4 'roadmap', DDR5 on a consumer level is probably 2022 at the earliest (although this is strictly speculation based on historic trends).