Richard isn't just an observer though. Remember, he's the one who basically got Locke appointed the new leader of the island and doomed Ben's roll as leader. When Locke failed to "prove" himself to the Others by killing his father and the Others had basically given up on him, it was Richard that secretly gave Locke Sawyer's file and that in turn allowed Locke to "trick" Sawyer into killing Locke's father. Locke then took the credit for this and "proved" himself to the Others. Without Richard doing that Locke would never have gained the Other's acceptance. In fact, you could say that Locke doesn't deserve to be the Other's leader since he never actually passed their test by killing his father himself. Sawyer on the other hand...
Another person of interest, along with Richard, is the lady who is the Sheriff. We've only seen her the once at Juliet's trial, but she also seemed to have lots of power over the Other's society acting as judge & jury for any crimes committed by the Others. Apparently even Richard doesn't have that power. She must have been the one that banished Widmore back in the day. I wonder where she is now? With the other Other's at the Temple? What would her views on Ben's return be? And the things he has done like trying to kill the Other's leader? They were going to put Juliet to death for killing that one guy, I can only imagine what they would do to Ben.
Also, as for going on and off the Island, I wonder how Richard managed it back in the days before the sub? How much power, money & influence do the Other's have off Island? They own/run Mettlework Bioindustries out of Portland and they must have other business's going. How many Other's are there off Island? Ben had all those passports and such so he must have been coming and going quite often. Heck, he even had agents running butcher shops in LA. They (the Other's) must have lots of connections off island, but why? Is it just for the fight against Widmore or is it for something else?
I assume Richard is like a senchel for the Others. He handles all the day-to-day affairs, keeps track of who is where, doing what, etc... Sort of like the lead (only?) bureaucrat of the Others. He makes sure everything runs smoothly for whoever is in power.
I'm going to put it into film industry terms for the hell of it:
In film industry terms the Island is the "Studio". A big, powerful orginization whos goals are to remain in business and stay afloat for the long term.
Leader of the Others (Ben, Locke, Etc...) is a "Director". They call the shots for a certain amount of time making sure a certain project is handled.
Richard is like the permanent "Producer" on the Island. He works for the "Studio" not the Director. But his job is to make sure the Director is doing his job and making sure the Director has everything he needs to run thing effeciently. Producers also have to think longer term in what's best for the "Studio". They bring in new staff, look for rising stars who could be future directors, etc... While helping the Director finish the project. And if the Director isn't doing a good job, he has to get someone else to take over, because the "Studio" comes first.
That's how I see Richard. The permanent Producer, working for the Island but his job is to help the Director get things done.