Mandoble

2.1.10 Windows:
Passive mobs at surface daylight: NONE in 30 mins test (with 2.1.8 I got few spawn in the same area, now none).
Hostile mobs at surface during night: Normal (as with 2.1.8)
Nether: NONE

1.2.9 update (Windows):

• Passive mobs spawn again, but I've not seen a single one spawning near my farm (full of tamed mobs).

• Hostile mobs spawn normally, but I've not seen a single one spawning near my farm (full of tamed mobs) out of illuminated areas.

• Nether spawn is as broken as before.

So sadly after this update MC Survival is still not worth a pen.

I can confirm that ocelots, wolves and parrots spawn and can be found. Ocelots and parrots are supposed to be rare mobs so I have no problem with their very limited presence. The problem is that the very limited presence is common for cows, pigs, etc.

In the Nether you have some spawns when Nether loads, once you kill these mobs the Nether gets almost empty as new spawns are very very uncommon.

While hostile mobs still spawn by night, the spawn curve seems weird, from very high to very low/null. All of a sudden you see several of them spawning even in groups, as you kill them the spawn rate decreases until it reaches a minimum or even none. Tested several nights in a plain in the overworld, same effect in every test. During day, the same problem of passive mobs with minimal or null spawn rate.

With 1.2.8 passive mobs spawn rate and number is close to 0 during day light. Tested a new 1.2.8 map for more than 10 hours. Hostile mobs seem to spawn normally during night while passive mobs don't spawn at all in very large areas or the spawn is minimal (one single animal in a very large area of the map). Finding a cow is a hard as locating an ocelot in a rain forest.

For some reasons this issue seems to be present since the tragic Better Together idea. This regression renders Survival maps worthless to be played, it is a game breaker.

In fact, this is a CRITICAL game breaker that renders Survival games worthless to play. 1.2.8 Windows 10 is affected while not listed in the Affected Versions of this ticket.

It affects to 1.2.8 as well, hostiles seem to spawn by night, passive don't at any time except at very low rate at the beginning, later no more passive mobs at all.

Which could be similar to MCPE-21856.
In 1.2.8 hostile mobs spawns apparently well by night, passive mobs start with a very low spawn rate during day and at some point no more passive mobs are spawned at all.