I've got an idea for your new spawner system:

Could you add a rule to make the new spawner spawn entities around a player from the biome spawn list the player is actually in or even better, the biome the (random) spawn block in a defined radius is?

Something like this, which would save a lot of rules for something like just increasing the vanilla spawn cap:

[
{
"mob": "minecraft:villager",
"persecond": 0.5,
"attempts": 20,
"amount": {
"minimum": 2,
"maximum": 5
},
"conditions": {
"dimension": "minecraft:overworld",
"mindist": 5,
"maxdist": 20,
"maxpassive": 50,
"fromspawnlist": true
}
}
]

This is implemented for the next version. It works as follows:

{
"mobsfrombiome": "monster",
"persecond": 0.5,
"attempts": 20,
"amount": {
"minimum": 2,
"maximum": 5
},
"conditions": {
"dimension": "minecraft:overworld",
"mindist": 5,
"maxthis": 150
}
}