There are excellent ranked teams on the Republic. In no particular order:
Hostile Takeover
S Key
LD50
Hoth Ski Patrol
Have a Nice Day
Slackers
WAR
Good luck!
It's not that people don't want to help, it's just that very few people play that spec anymore! Which is unfortunate.
There are videos and guides on Youtube about Annihilation but most of them, if not all, are out dated.