Just like nests migrate I see the common spawns shuffle a little too. There have been regular Machop spawns throughout my town. Not more than one or two here and there, but consistent. I live on an island and Dratini is very common along the shore: both secluded beaches and the tourist-y parts of town. I would be sad to see her go!
Dratini scarcity
Does anyone else feel that Dratinis are becoming scarcer than ever? I have a spawn point that is reachable from inside my house which spawns a water pokemon every hour. Before the Halloween event, I used to average about one Dratini per day at home. After that event, it slowed to more like one per week, although I'd occasionally get two in a day, or one on consecutive days, etc. Now, I haven't gotten one for 2-3 weeks, and probably only one in the last month.
I thought maybe they decreased the Dratini spawns and compensated by having them hatch from eggs more frequently, perhaps to combat spoofers, but now they are apparently reducing the hatch rate as well.
This is kind of a bummer, because getting semi-regular Dratinis seemed like one of the few advantages of my particular location/biome (along with being able to get all the Cloysters and Piloswines I want).
BTW, I almost never used to get Squirtles at my home spawn point, and now I get about one per day. I even get more wild Wartortles than Dratinis now.