1 Peter 2: 2: "As newborn babes, long for the spiritual milk which is without guile, that ye may grow thereby unto salvation." (American Standard Version) Spiritual milk is also translated as "rational & unadulterated milk".
JWs may still possess "some of the core teachings of the TRUTH". The problem is, in the course of crafting adjustments over the years, the organization has added "unessentials" that have somehow beclouded the truth. That is where the trouble lies. Once pure milk now becomes adulterated.
I have come to re-assess the preaching work since I and my family am are still doing it. What I do is to find ways to preach matters that can help the household appreciate basic bible truths - a combination of what the future holds and practical day-to-day application of scriptures - not much about WT literature. What makes me feel better is if I am able to let the other person smile for learning some good things about the Bible, e.g. family, personal problems, work etc. The emphasis is for them to realize the Bible is no ordinary book. It can be a lifeline. When principles are applied properly, it will give refreshing results. This is the positive side of preaching. But to impose on others to believe some doctrines that we ourselves do not believe anymore or having doubts to say the least, well, that's making me uncomfortable.
In the preaching work, we share the good news, hope, it's positive energy. We feel the Holy Spirit is guiding us. We channel their attention to the Bible and its infinite wisdom. This becomes like a commercial break for them who are so busy. Preaching and teaching others to change their lives for the better, making them praise Almighty God Jehovah and his wonderful works, these are the activities that will be hard to just let go.
And when things get really worst, I think it may just boil down to this: Choosing the lesser of 2 evils? :)