To be honnest i don't like too much things in the new system. I will explain what i don't like.
Spawn can change every 12 hours, it's really a bad idea. Furthermore, we saw this month rain changed to rain like 15-20 times this month.
Imagine you have support spawn, you use bms for farming gligar for example, and then 12 hours later spawn change to rain. If you don't like rain spawn and you wanted to farm only support spawn, this system is really bad for this kind of players.
I purpose to lock spawn for 3-4 days (duration of bms). Then after this delay, spawn can change and players have choice to vote to stay or remove spawn.
The rate of 12.5% is really too low, 25% will be better. I have already made 24 flamethrower in PvP and never burn. So now imagine with guild island, if rng is bad, the spawn will be same for entire month, i don't like this.
There were too much players for guild island, and guild island spawns must be deserved.
I saw really often set rain to rain, more and more... that was really boring.
Another thing I would like to comment, it's about new spawns in guild island falls. It's good thing to add a new spawn, it was apprecied, especially with pokemon non huntable usually. It's good add. However, i think some poke should be deleted of list of non huntable pokemons. Who cares about Rattata-Alolan, Raichu-Alolan, Diglett-Alolan, Meowth-Alolan, Rockruff and Dhelmise ? Maybe 10-20 peoples per server, not more i think.