i recently returned after a 1.5 year or so absence, and ive been getting oracle quests 2-3 times a day or more, when before i didnt always get 1 a day. has gotten an increased rate of appearance while i was gone, or am i just getting lucky (or was my past self unlucky, lol)

You're just getting lucky. I've found, for me anyway, Oracle quests tend to come in bunches. I'll get 3-4 in a short period of time, then none for a while, then another group all together.