Ngondro certainly isn't for everyone. Perhaps it's too easy for the lamas to give ngondro as the prescription for your practice, especially in the beginning. However, who among us is qualified to judge what practice is best for themselves? Deluded beings are notoriously unreliable judges. One would think that a person trained to be a lama and authorized by the lineage to teach has at least a little bit more clarity and realization than the average deluded being.
surely they should be preliminaries, not the main event....
This, udawa, is why many lamas realize that the translation of "ngondro" (sngon 'gro
) more literally as "Preliminary Practices" is problematic, mostly because of the negative connotations that come with such a term and how many of us want to be practicing the "higher" teachings (meaning that we consider stuff like ngondro as somehow beneath us or something to hurry through before we get to the "real" practices).
It would be better to consider translating ngondro as "Foundational Practices" since the purification of negativity and accumulation of virtue done in the four sections is what allows the other practices to be so effective. Without a good foundation, most things cannot be built. Also, don't forget that ngondro is a complete practice which can lead to full enlightenment without anything else being needed. Therefore it could very well be the "main event" for many practitioners (even some of the great masters past, present, and future).
In fact, many of the greatest lamas such as Jamyang Khyentse Wangpo, Jamgön Kongtrul Lodrö Thayé, and others are said to have gone through ngondro multiple times at various points in their practice due to how effective it is. Sometimes they even were able to reveal terma as a result!
I highly recommend reading the introductory first several pages of Dzongsar Khyentse Rinpoche's book Not for Happiness: A Guide to the So-Called Preliminary Practices
to see what I mean and get a different view of Ngondro.
Follow the link below, and then tap/click the cover picture (notice it says "Click to Look Inside!"):http://www.amazon.com/Not-Happiness-So-Called-Preliminary-Practices-ebook/dp/B007PTA8WE
"The Sutras, Tantras, and Philosophical Scriptures are great in number. However life is short, and intelligence is limited, so it's hard to cover them completely. You may know a lot, but if you don't put it into practice, it's like dying of thirst on the shore of a great lake. Likewise, it happens that a common corpse is found in the bed of a great scholar." ~ Karma Chagme དྲིན་ཆེན་རྗེ་བཙུན་བླ་མ་རཱ་ག་ཨ་སྱ་མཁྱེན་ནོ།