He has everything the way he wants it and only takes interest in the Hobbits as an amusing curiousity. The Old Forest herded the company to Old Man Willow at his direction.
As master of his realm he surely knew how the Old Forest worked to funnel trespassers to Old Man Willow. It appears he has had some experience with the Willow before and has learned how to exert some control over it.
His motives are no more evil than the closed and innocent nature of the Shire, and most of us hope that they keep that innocence and never have to deal with the evils of those outside their realm.
I don't think his motives are particularly evil, but they are not all together innocent. I think this experience is an early lesson in caution for the company because he knows too well what evils they will be exposed in the outside world.
Hmm. I don't know that Tom's age will end with the ring.
Don't wish to spoil, so this point can be discussed in more depth when his name appears for the last time.
You shouldn't shock my sensibilities like that! ;~D
My apologies....but it did get your attention. :-)
I only continue to question this interpretation:
It appears he has had some experience with the Willow before and has learned how to exert some control over it
Yes he can control Old Man Willow when he arrives on the scene, but I think he is master of a not-completely-obedient old grumpy tree. If Old Man Willow draws unsuspecting victims to him, I think this is of his own accord. Tom speaks to him as one would chastise an errant dog jumping up on a visitor, not as if OMW had fulfilled some order or plan of Mr. Bombadil. In other words... He can control the tree, but it is reactive, rather than premeditated, IMHO. He is the master, but that does not mean he controls, rather he oversees what happens and decides whether to do anything about it.
On second thought... Why is it not innocent to decide not to participate in the outside world's issues? ... True, he knows all about the evil that exists, and has chosen to fence himself off from it. I think it is not immoral to just protect your own and let the evil pass, or we would all be evil if we are not actively fighting every evil that we know exists.
I have thought on many occasions that the survivalist-types who have bugged out and headed for the hills might have chosen a fairly good way of dealing with an imperfect world. They remind me of Bombadil, except I don't see them singing silly songs as much.