Its gone from, "Summon a DIFFERENT copy of Succubus from your graveyard to a random row" to "Summon THIS copy of Succubus from your graveyard to a random row".
In other words, its changed from, 'If you have two succubus in your graveyard, summon one of them' to, 'if you have two succubus in your graveyard, summon both of them'. (Since I'm assuming the game logic currently has the first succubus's ability trigger, then checks if there are anymore succubi in the graveyard, finds none and then leaves the first there where as this new wording implies it now just checks if there is another succubus for each of them at the same time and so they would both trigger and resurrect. Otherwise the ability would not actually change and they would not bother labeling this as an 'Ability change' and instead would labeled it as, 'Wording changed')
Basically its changed from a weird pseudo engine where if you could get two into your graveyard you could keep eating them and summoning one of them back each turn to becoming a bit like a delayed foglet where eating one does basically nothing, but eating the second summons 8 points onto your board. Then if you do that with adrenaline in round 1 or 2 (purifying them) when the round ends they go into your graveyard and pop back out again for effectively 8 points of carry over.
Its probably not going to actually be that insane since it requires playing and consuming a 4 that does nothing, just to later play another 4 that requires a consume to do a slightly better version of what the other 5p thinning cards do already, BUT it has a potentially nutty upside! And it makes Dol Dhu Lokke potentially better since if the Succubus works the way it looks like it does, 8p to more constantly get 8 or even 12 points of carry over would actually be pretty insane!
And if it DOESN'T work as carry over, again, Dol Dhu Lokke still potentially gets stronger since as written, it sounds like if you put 3 succubus in your graveyard, three would come right back out again which would be pretty good.