Will you eventually create it as a submod for radious? I was waiting for something like this for a long time and finally it is here.
Big thanks to you man, this mod was desired for a long time! :D

Thank you lots!

@{LUD} Invade Me
What I did was download the Rome 2 Assembly Kit then open:
Steam\steamapps\common\Total War Rome II\assembly_kit\raw_data\EmpireDesignData\campaigns\main_rome\victory_objectives.txt

From there, I used CTRL+F to search for MP_COMPETITIVE and replaced that line with:
CONTROL_N_REGIONS_INCLUDING;
total 173;

I also scrolled down to where it says //** MP CO-OP ** and changed the primary objectives and payload with:
type CONTROL_N_REGIONS_INCLUDING;
total 173;

I did keep the other victory objective requirements for co-op but I believe by default, you only needed like 40 regions to win.

I went back and changed this for every campaign and faction. You can also use this file to also modify singleplayer victory objectives. From there, you just have to use the BOB on the assembly kit to create your mod. Once your mod is created, you will find it in:
Steam\steamapps\common\Total War Rome II\assembly_kit\retail\data\

Hello! Did you basically delete this?

//** MP VERSUS **
victory_objective
{
faction rom_rome;
campaign_type mp_vs_normal;
mission
{
victory_type military;
key rom_victory_mission_military_victory;
issuer CLAN_ELDERS;
primary_objectives_and_payload
{
objective
{
type MP_COMPETITIVE;
}
payload
{
game_victory;
}
}
}
}


^Like this entire thing? And that you did so for every faction? I don't know how "much" I have to delete. How many of these brackets you know

Special thanks to Horace for his guide on how to modify victory conditions yourself for modern Total War games. Here's a link to his Warhammer II mod.