[Boromir88]

You bring up two valid points. With the whole "circle" idea as not really being evil. The characters you see (especially the hobbits and Aragorn) go through "circular" patterns to become the people they are today.
For example you have Aragorn who wanted to be king from the very beginning of the journey, but the Aragorn at the beginning is much diferent from the Aragorn at the end. If you look at LOTR, after losing Gandalf, Aragorn was questioning what he had done. He was watching the fellowhips fall apart before his eyes, Boromir had died, Merry and Pip were captured and Frodo was off to Mordor with out telling anyone. Aragorn took the role as the leader after Gandalf died and he questioned himself and saw himself as a failure at the end of FOTR. But his determination and love for Merry and Pip led him on. At the end of the book Aragorn is a confident, loving, and turns out to be a great king, great leader.
The hobbits all went through changes and you see that in the scouring of the shire. Merry and Sam in particular stepped up and became leaders to drive out Saruman. All the fellowship characters had went through a transformation (which you can think of as a circular path, since you need to go off the straight road to go through a transformation) and you see that by the end of the book.

Your other valid point was the way Tolkien wrote it was probably the best way of doing it. You mention Glorfindel replacing Pippin. If pippin wasn't in the fellowship Faramir would of died, end of story. Faramir did a lot of things behind the scenes in LOTR, he was an adored captain of Gondor and his death would of been tragic. Glorfindel is no doubt a better fighter to Pippin, but come on Denethor wouldn't of let Glorfindel stay and keep him company. It had to of been someone like Pippin to tell Denethor about the journey and to warm his heart, for it was written that Pippin brought a slight warm of Denethor's heart. Pippin eased Boromir's death. Glorfindel probably wouldn't of cared about Faramir, no Pippin means Beregond is not warned and means Faramir is dead. Also, Gandalf used Pippin to keep an eye on Denethor. Sometimes I wonder what would happen if Boromir hadn't of died. Well if Boromir hadn't of died, probably means the hobbits wouldn't of been captured, which means most likely the company would of gone to Minas Tirith. There would of been no need to go to Rohan, Legolas and Gimli clearly said they would go to Minas Tirith, we know after was Boromir did Merry and Pip would of gone too, of course Boromir, and Aragorn wanted to go with Boromir from the beginning. If they hadn't of travelled to Rohan, Theoden wouldn't of been free and Rohan would be in control of Saruman. You had Gandalf during Amon Hen I believe he was still in Lothlorien, there he fought wtih the dark lord when Frodo put on the ring. Gandalf knew Rohan needed aid and probably would of tracked down the company and told them they needed to go to Rohan, but by then it might of been to late. Who knows this is only speculation. The way Tolkien wrote it, there probably could of been no other way but it is always fun to ponder.