so why are all the other planets not done in this fashion instead they seem like carbon copies of each other? the music even is totally different from all the other planets and dare i say the game.
Glad you're enjoying the game, as for your question there is a very simple reason for it
Most of the missions you just played through are a few years old now, most of the planets were designed a long long time ago when they had fewer staff, and less sophisticated tech. New Romulus is a relatively new addition, added in the last season (Season 7) and it was the biggest and most ambitious planet/"adventure zone" to date.
I agree, it's excellent and is mostly considered a great success - so I'm sure we can expect more in the future.