When STO came out in 2010 it should have had just one faction, FED. Then when the first major expansion came out in 2013 the KDF (instead of the RRF) would be introduced and the half-faction Ferengi Alliance. Why? That would have given you guys a HECK of a lot of time to create and develop the KDF storyline tailored to them rather than having the current state of... 1 full faction (FED) and 2 half-factions (KDF/RRF). As it stands the majority of story arcs don't reflect the "divide" or "uniqueness" that you want us to perceive between factions. You should have saved the copy/paste story arc for when you introduced the, Delta Alliance. This way you would have also had more time to work on the Fleet system and eventual integration of cross-factioning.
You could introduce half-factions periodically for what they are rather than advertising them as a full faction (false advertising). Full factions have their own unique story arcs up to the level cap that can only be done by that full faction. Half-factions such as the RRF only have one story arc that is unique to them while the rest are copy/paste from their "chosen allied faction". Down the road the 3rd full faction would be the Romulan Star Empire and introduce the half-faction: Romulan Republic.
After the Delta Quadrant you should have held off on the Iconians and instead headed to the Gamma Quadrant where we would face the Dominion and be introduced the half-faction: Cardassian Union. Why? Because the Iconians are supposedly the most ancient and advanced and have ruled the galaxy for 100,000 years. The problem with playing the "most powerful bad guy" card is that after you dealt with them you are forced to come up with another "most powerful". Thereby creating a Dragon Ball Z complex wherein you just keep making up new (and probably unoriginal) adversaries to combat. Eventually they would reach Douwd and Q level. Then what...? In the Douwd's case with a thought we are all dead. In Q's case with smile and a wink and a sarcastic remark we don't exist.
I think you played the Iconian card pre-maturely. So quick to move on to the next stimulating thing rather than flesh it out. There is still a lot that you guys haven't milked from the Borg threat. Along with them you could have introduced another half-faction: The Cooperative. But now that you played the most powerful bad guy card you can't go back to a weaker bad buy.

The first
Belfast was commanded by Captain Ve'Kal Shon until its destruction in 2409. A new ship was commissioned bearing the same name and registry as special dispensation to then newly promoted Captain Edward XIII for his pivotal role during the renewed Dominion War.
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The romulans only being a half faction is not really true, since they have a story arch that is just as good (even better actually) than the other 2 "full" factions (the only thing missing are fleet starbases). Considering the workload to do a faction, it just is a full faction. Story missions don't write themselves.
Should cryptic introduce more factions like that? Hell yeah, but it is a lot of work and considering that they have to run a business, some factions just don't pay off.
If you want to be a cardassian, ferengi or whatever, you basically can do so with lockbox ships.
Iconian were played prematurely and not intense enough. As of yet, the borg, undine and tholians seem to still be a bigger thread to the quadrants than the iconians. A red alert and 2 combat zones should be implemented to give the iconian threat a more urgent feeling.
Anyway, what is done is done, it could actually be worse than it is right now. The game after 5 years is still rough around the edges, I'd rather have them polish it up some more than introduce more and more content...but I guess they have to to stay afloat.
Romulans were after F2P.