Is Lord of the Rings too short?

In the foreword of my edition of LoTR Tolkien says that the only criticism he might agree with is, that LoTR was too short. What does everyone think? Would it be better if longer and what would you have in it to make it longer?
At first I thought LoTR is perfect length, but I would like more on Striders early adventures, both with Gandalf and alone. Remember when Strider says that he travelled alot with Gandalf, and how much he learnt from Gandalf. Also how he travelled among men in the east, where many of the men were corrupted by evil, all this would make a great story, and be more of an insight into character and developement of my fave character, Strider.
Maybe Tolkien should have written another book, Adventures of Aragorn