I think its more than possible that we might see Eddy again in a sequel.
He's almost Bobba Fett like in his role and popularity, as in he wasn't the big bad villain but one of the guys who was hired to do some dirty work by the main villain.
And like Bobba Fett, Eddys swagger and personality secured his place as a fan favourite.
And despite his apparent death at the fate of the Sarlaak pit (a seemingly inevitable death once you have fallen in) Bobba survived by fighting his way out and lived on in the expanded universe.
If I remember correctly Eddy still had his gun, and I'm sure he carries a knife too.
The way he fell looked like he would have landed on top of the creature, perhaps killing it depending on the height of the drop. Once on the bottom of the pit Eddy could have shot the remaining creatures and made his escape.
Even being bitten in the neck isn't gonna stop Eddy Raja, a direct bullet wound to Nathans stomach wasn't enough to put him down. These similar fatal wounds provide an interesting similarity between Drake and Eddy.
Lets not forget that stranger things have happened TWICE now in the Uncharted universe.
And the most important thing to remember...
Don't Mess With Eddy Raja!!!!