Whether they may end up having a point about it, isn't something relevant yet. It is seen as bad to go with the ones considering a high dragon to be some reborn Andraste. The ancient temple is found on the Mountain Top after the Warden has battled through the Ruined Temple and the. It entails a series of challenges in The Gauntlet that test the Wardens faith to ensure they are worthy of finding the Urn of Andraste. At least within DAO context, a selfish or bad character will go with the cultists and a selfless and good character will go against them and for the temple. A Test of Faith is a quest that is part of the Urn of Sacred Ashes quest line. In any case, it isn't likely that the DAO actions will be a *big* deal one way or the other, though sure I'd still try to RP appropriately. But there's perhaps signs of explanations in the future.
While the Temple of Sacred Ashes returns in DAI, the matter of the reaver dragon worshipers isn't really directly addressed, and the whole idea of dragons speaking to worshipers isn't a big explained deal yet. In terms of series story consequences, I don't think any of this has been directly addressed. Generally a good character would kill the dragon as being a dragonslayer in this point of the series is seen as a good thing (this continues in DA2 and DAI, though DAI starts adding a tone of tragedy to some of it).
