Will Kürlich Kerl
Banned
What happens if Louis V of France survives for another twenty years and had a son with Adelaine-Blanche of Anjou?
You'd still have a very strong nobiliar opposition to Carolingians. With the election of Eudes, Robert and Rudolf, and the general opposition of Ottonians, Louis V would have at best a troubled reign.
Frankly, I don't think he could last 20 years without at least some big attempt at removing him, while he won't be alone on this.
Not that a return of Carolingians isn't doable with Louis of Lower Lotharingia (we discussed it a bit with manuel), but Carolingian kingship was enough fragilized by the late Xth, that you need some major Robertian crash (Robert II not living up to be crowned during his father's reign, for exemple)
Carolingian succession would be really safe only when Louis's hypothetical son could inherit (probably crowned during his father reign) and with Robertians being significantly weakened : Blois recieving the Dukedom of Franks, in all probability (which is going to be problematic, as Robertians already began to decline in Western France while Hugues was crowned, and that Blois'star was rising).
The main changes would be to see French kings still trying to get Lotharingia, or at least part of it, as almost all Late Carolingians did. Meaning an Imperial/French early opposition.
Eventually, Carolingians wouldn't benefit from much royal demesne, and may have to play even more importantly on the political balance to hope keeping enough power. Basically, doing what Capetians did IOTL but with a more important rivalty on their eastern borders.
(Arguably, it could as well meant less involvement into Western French nobles's war, as with Normans, Flemish, Robertians and Angevines; while a royal support for a given side, mostly driven by the search of a balance, would still be a given)