Sure you do, they both tell you. One's an ancient snake guy who was a servant to Gwyn and is now seeking Gwyn's successor to link the fire and stave off the Dark. The other's an ancient snake guy who's more of a rebel that wants to overthrow Gwyn and end the Age of Fire and from what he says and what you see his motives are highly suspect. Frampt isn't telling you the whole story either but he seems like he's altruistic.
And the turtle with the pope's hat tells you that he is the steward of the Church of Vows where Radagon and Renalla joined the houses of the Erdtree and the Moon in matrimony, and is full of information on both of these individuals. Which he gives you freely, directly and unobtusely. He doesn't know everything, but then, why should he.
You never know
why he's a big goofy turtle but you know what he's about (serving the Erdtree and the Academy), what he wants (to guide the Tarnished on their quest) and why he wants it (because everything is shit). It's a fantasy setting, you can make some suspensions of disbelief.
Otoh, DS1 is completely obtuse on the matter of what these ugly snakes even are, where they come from, why one of them is serving Gwyn when he was a notorious exterminator of dragons, what the other snake even has to gain from extinguishing the flame, and why there are a whole bunch of other snakes all hanging out somewhere underground. You don't even know if they're really snakes, or have bodies with limbs and a very long neck.
Gideon and Ranni never plainly tell you who they are, the things they want or why they want them.
You figure out their motivations as you progress through the game. Ranni has an extended series of monologues where she details her backstory, her plot, her reasons for doing what she did in the past and is doing now, and her end goal (becoming the new goddess of a new age).
Gideon also tells you quite plainly that he is seeking to become Elden Lord, and that his best bet for the time being is helping you open the Erdtree's inner chamber. After you accomplish this, he beats you to the inner chamber, and then reveals that he's looked into the mind of Marika and has given up any hope of becoming Elden Lord, because Marika wants one of the Tarnished to kill the Elden Beast, and he thinks that it's impossible ("I know in my bones that no Tarnished can defeat a god").