As was stated above, allowing a Romulan Faction to have Romulan and Reman BOFFs is certainly not the same as allowing the Fed or KDF to have them.
You might as well be saying: "how useless that I can have a KDF BOFF when the Klingon Faction also has them.
STO is about my Liberated Borg Federation Captain with his Breen 1st Officer, Jem'Hadar Tactical Officer, Liberated Borg Engineering Officer, Android Ops Officer, Photonic Science Officer, Gorn Science Officer, and Reman Medical Officer jumping into their Jem'Hadar Carrier and flying off to do missions for the new Romulan Empire. But for some players allowing a T5 Connie to be used breaks the canon in the game.
Are you kidding?! That feature episode would be great for a romulan. A neo loyalist wants to help the Remans to gain their support, while a loyalist, wants to eliminate them to make an example of what happens when you both steal from the Tal'Shiar and betray the Romulan people (by leaving) It would require very little dialog modification, and and it can be slide into the faction-ing they already have shown the new Romulus has already. And I'd expand the mission that you could get a Romulan BO (maybe a Tal Shiar operative) for completing all the Tal Shiar objectives
..and like children playing after sunset, we were surrounded by darkness." -Ruri Hoshino
But a Jemie can't kill a founder its against his religion
Actually, yes, they can, as shown in To The Death and other episodes. The Founder's control over the Vorta is nearly (not completely, as seen by the Weyoun clone that turned traitor) absolute, but their control over the Jem'hadar is tenuous at best. The Jem'hadar don't even universally believe in the Founders (Purgatory's Shadow/Inferno's Light), most believe it's the Vorta who are actually in charge.
Which is why they need Ketracel White. They can't guarantee Jem'hadar loyalty, but they can guarantee the death of disloyal Jem'hadar.