Just returned to the game after some time off to try the new Update in singleplayer. I was glad to see the "conquest" feature is here, it was one of the features I would have liked to see when I initially started playing the mod. However, in its current state, it has missed the mark and lacks two features that make a world of difference: ability to change decay time and enemy spawning.
TL;DR: with the current setup, you actually do not conquer territory, just get some allied spawns around you, whose numbers are low, the enemy is still there and even this small benefit is lost quite quickly due to very fast decay time. My suggestion would be to enable commands to be able to influence decay time and (if possible) no enemy NPC spawns at all (when a certain ceiling is reached). If NPC spawn is fully biome related (therefore not technically possible), at least enable tweaking ally NPC spawn rates and decay time. For server players: please ignore all this as it does not affect you, since admins can ignore these commands fully. Do bare in mind however that a THIRD of players plays on singleplayer, based on latest survey, so the freedom to tweak these settings would make a world of difference for those not playing competitively.
First issue: decay time
Currently, decay time is set by the system and is both very fast and contradicts MC mechanics, by decaying even when the player is not in a chunk. You can spend an hour in a chunk and reaching high alignment with a faction, still decay of the conquered territory will be so fast that in no-time you lost the territory, unless you constantly remain in that area. Which is quite impossible, if you want to conquer all of the enemy areas. I'm pretty sure this is done on purpose, to avoid (on servers especially) an imbalance resulting from too slow a decay, so that more active (PvE) players would basically conquer the map in no-time, without other players having the chance to repossess conquered territory. It ignores the fact however that (based on latest survey) a significant part of players plays on singleplayer (33,7% of 1393 respondents), where there is no PvP and therefore (permanent) conquest would be a fun purpose to set.
Since the conquest RATE can be set through commands, this basically can be set in a way that you get so many points for kills that with current decay time it will never fade away, so basically permanent "conquering" is enabled as it is. So if the intention was to not allow for an imbalance, it is there if a server decides to allow for (virtually permanent) conquering. It makes no sense therefore to restrict changing decay time for this purpose. Furthermore, the disadvantage of the current setup (i.e. decay time changing disabled, but conquest point rate enabled) is that if I want to make a territory be conquered permanently, I will have to set the conquest rate very high (so that no matter the decay time, it remains my territory), but this means that with a few kills I have already conquered an area, which makes no sense either.
My suggestion would be to enable changing decay through commands, so that one third of total playerbase can set the rate of conquering for themselves in singleplayer (and some servers as well where players are open to such change). If this is technically not an option, please at least enable a permanent conquering setting, which is enabled when reaching a certain level of conquest rate, able to be set through commands.
What this would look like: a command setting conquest decay speed vs current speed, for example value 10 would mean it decays 10 times slower. Value 1 means at current speed.
/conquest decay [value]
Alternatively, by reaching a "ceiling" would make an area permanently conquered. Value is the ceiling value of conquer rate. For example Value 100 means that once you reach 100 conquer rate, your decay in that chunk stops (until reset or until an enemy player takes it back, in case of multiplayer servers).
/conquest permanent [value]
Second: enemy spawns
Even if the decay is fixed, the bigger issue is what "conquest" really means here. As the last comment before me mentioned, it is hardly a conquest when your allies spawn at still a neglectible rate in the conquered territory. I reached a 100+ conquer rate in Dol Guldur to try the feature out, but aside from small groups of Elves, the (conquered) Orcs seem to spawn at the same rate as before, with the only change that the few spawned Elves ignite the occasional fights at the periphery of my location, not influencing my PvE at any extent or the conquering of terrain. Again, if we look at singleplayer, it would be a fun goal by itself to be able to enable permanent conquering, which means you basically populate the enemy territory with your own troops. I can even imagine some servers who may blow some new life in the game by motivating players to not just PvP but go out there and conquer terrain or take it back if conquered.
If there is a technical boundary to doing this and enemy NPC spawns are biome related, so that their spawn numbers cannot be influenced, then I would sugges to replace the NPC from enemy to ally in those chunks that have reached a certain ceiling. If this is technically impossible as well, then perhaps the number of allied NPC spawns could be increased to a much higher extent than it is now and/or those of the conquered enemy decreased. I think that we can only call something "conquered" if there is a (permanent or at least temporary) imbalance in favour of the conquerer. Otherwise it is more like a reinforcement or as if you have more hired troops (but you cannot control them).