I understand what you are saying. The way I see it, Eckhart's teaching is often the first glimpse of awakening for many. In a sense it is a wide gate, it has helped many on a large scale. Often early on there is a habitual need to do something to awaken, a practice of some sort, and that is fine. So a teacher attempts to provide what the students are ready for. The practices are kind of like training wheels, that eventually we see that we don't need them anymore, and shed them on our own. Actually compared to many contemporary teachers, what Tolle gives in terms of practices, is very minimal. He often says in his talks that he prefers not to give practices. He also says (not in so many words) that early on it seems as though we are doing something to awaken, when actually what is occurring is that awakening is happening through us, in spite of our efforts.I'd like to add that Eckhart does seem unusual in some ways because his teachings do seem to leave out certain aspects related to awakening. While I can certainly see the resonances of Advaita in Eckhart's teachings about watching your thoughts, it also seems at times that a lot of what he discusses involves practices or things we should "do", which seems that it could fuel the belief that you're a separate, individual "doer".
I think what is important is that we not fixate on any one facet of awakening.
Tolle may be the first stop on the train of enlightenment, for many, but not necessarily the last stop. There may be many stops, perhaps an endless unfolding of realizations. Eckhart does not claim that his is the only teaching one will ever need, or that it addresses all aspects of reality, although his students sometimes make such pronouncements. Perhaps that is the case for some students, or perhaps it is just wishful thinking. When we are new to awakening, we often wish it is was simple, with such thoughts as "why can't there just be one book to read or one simple method." One quotation to remember, one pointer. Frustration can set in, sometimes this leads to withdraw, or fixating on the realm of emptiness or meaningless. That can be a trap.
Emptiness as described by Advaita, is only one facet of the jewel of awakening, but there are many other facets. We don't want to anchor down in any one realm, and say "this is it, I have arrived", but rather stay fluid and in the flow of life. What is most helpful for me, is coming to that place of loving truth for the sake of truth, for no other reason. No goals, no shoulds, no expectations. Just a simple relaxing into Grace, in gratitude. Being sensitive to that inner movement and be willing to be led by it.
Relax and enjoy the moment