Pokéforce won't need legendaries to be popular. It has many other opportunities/features to offer that other Poké MMOs could only dream of offering. Not only that, but the game also has a wider target audience. It won't only interest Pokémon fans.
NGL that's exactly the reason they should add the legendaries permanently and obviously ban them of
EVERY conventional pieces of content of a Pokemon MMO game. No legendaries in PvP, no legendaries in classic raids, no legendaries in NPC battles, etc.
This team has the abilities to create whatever they want (that's my conclusion considering they are creating a whole region).
Then why not building
a whole ecosystem around legendaries ? Legendary PvP (temporary event ? That could be a cool endgame piece of content, with fair rewards like chroma charms, exclusive cosmetics based on legendaries mons idk), legendaries (world) raids, legendaries pokemon league (an endgame pokemon league). There is so much to build around those mons that can easily become part of the endgame content. Cheap but efficient ideas. And by that you're making true the dream of PokeMMO players : getting access to legendaries pokemons. That's such an easy way to "steal" the PokeMMO community.
I will just take myself in example : +2k hours on PokeMMO. I'll give a try to Pokeforce, the team deserve it.
Now tell me you're gonna add the legendaries mons : I'm on your boat FOREVER, goodbye PokeMMO.
I want the team to consider this.
(((And nobody likes KOTH in PokeMMO btw, just a fact.)))