I'd also love there to be more of those events, but the dev knows that and will add those eventually, especially together with more story tidbits. I'd still say the game is VERY worthwhile now, though even if I agree that it would benefit from some more events.
There are actually quite a few of those random events in the game, but the way they trigger is complicated (and a bit limited), and might be contributing to the way you're seeing them.
In total, there are about 90 of them. However, this list is roughly split three ways into groups that you'll only see based on the way you've handle previous encounters. So one group will appear if you've mostly had neutral responses, one for selfish, and one for altruistic. When you start the game, you're considered neutral, so you're usually seeing that same neutral group at the beginning of each game.
Furthermore, each of these major groups are split into 10 minor groups of 3. A minor group tends to follow a certain theme (e.g. childbirth, crazies, a certain gang), and they'll appear in a certain order. (E.g. you have to find the woman giving birth before you find her again later with the baby already born). At any time, 10 minor groups can be seen, provided you qualify for the major group (selfish, etc.).
Finally, these random encounters almost always appear in urban or suburban hexes. I.e. they involve people and settlements, so no woodland encounters. There are more hexes than encounters, though, and they are randomly distributed across the map. So you'd have to visit most of the map to see all of them in the same game.
These random encounters are separate from the "canned" encounters, of course. Things like Hatter, Zom Zom's, and the Strange Forest are all landmarks on the map, and usually stay put. They are also much more involved, often including multiple choices, backstory, and more detailed rewards and consequences.
My future plans include adding at least a few more of those "canned" encounters: major locations and people to interact with, discover clues about your identity and history, and maybe figure out how to protect yourself against the wraith.
Time permitting, I'd also like to review the random encounters, to fix up some inconsistencies and flesh out some choices.
However, I'd also like to move on to NEO Scavenger 2 at some point (and other games), particularly so I can move into the more powerful Haxe-based engines. Flash has served me pretty well, but is becoming a limiting factor (notably, making Linux, modding, and save games tricky). The sooner I finish NEO Scavenger 1, the sooner I can make a new and improved game engine.
However, quitting too soon risks upsetting existing customers. So there's a delicate balance to maintain. Overall, I'm aiming to do what I can until summer 2014, and hopefully have enough done for the game to seem "worth it" to customers. I'll continue to support it with bug fixes where I can, but I've been working on NEO Scavenger since early 2011, so I'd like to be starting on a new game this year!