Personally, I'd say yes. VS's Skyteam integration is actually a strong selling point giving the limits of their partnerships before.

I respect some others disliking Skyteam but I honestly cannot agree with them. AF long haul J and P are typically significantly better than BA, AFKL short haul Y is much better than BA. Conversely, BA within Europe is much better than AF KL but it is not something I tend to use much nor W. Long haul Y I'd say they are roughly equivalent.

Transiting at AMS or CDG (yes you've read this correctly) is actually a lot better than transiting at LHR these days with increasing flights that do not require security reclearing, and the generalisation of intl passport gates will make this yet better even when there is a non-Schengen-Schengen connection or the other way round.

Finally, it is typically easier to get good long haul J prices from the UK (if this is where you originate) on AF KL with one stop itineraries than on BA and partners, and your trip is fully protected which counts for a lot in this day and age compared to people who go through some contortionist move to do an ex-Wherever which sometimes goes horribly pear shaped.

The main weakness with AF KL was arguably their FFP but if you can now get VS's and still get the partnership, then yes, I can see how this will work to many. DL is a very decent option to and within the US (I'd personally say generally better than AA and UA but that's a matter of taste and specific patterns) and some partners such as KQ, KE and VN can actually be surprisingly useful.

So yes, whilst there will not be any silly exodus, I can see how this will lead to a small to medium amount of diversification and/or migration from BA quasi monopoly of some passengers. In particular I'd expect VS to be quite aggressive in discussing corporate contracts with new alliance benefits.