I played before temples were added. Their presence is definitely a bonus. It's a way for people to help their studio acquire diamonds when they don't have money to buy them. I had a little solo studio then. I was stuck doing only what I could with just notes because I wasn't able to buy any at that time. Also, around the same time, several career bosses were added. Before that there was a big gap after the one in Los Vengeles and I wound up getting bored of just grinding missions. As a result, I faded away from the game and returned later to find that star deleted.
I don't always like what the devs decide to implement but I'm glad that they actively implement things on a fairly regular basis. I've played games where it seems like the devs have gone into hybernation or even a coma. Things get stale really really fast. And this team does make changes some times as a result of player feedback. Altering the film trophies is one example. Making the party tickets 24 hours was another. There was another game I tried to return to that I liked a lot. When I was there before, the entire player base was begging them to to do something about the ridiculous mandatory PVP after a certain level. They flat out refused to budge on that and guess what. When I went back, there was no game.
As far as people being recruited away, that's up to whether the player is recruit-able or not. Some are. Some aren't. I've had a lot of offers. I even get them as the studio boss on the star that is one. I don't worry about people moving on. If they do, I wish them well...and shower them with epic bed feathers There are several in the studio I am in that were there when I joined on this star. I think I have only seen one player that was there for a good amount of time leave and join a different studio. In the larger studio I am in, it seems like if people leave, it is for RL reasons. I'm the newcomer there and don't know the full history, but I don't have the feeling that the big players are about to be lured off somewhere.