He is not suggesting a chop, merely a course to grow new roots for the tree (via "layering") creating a far superior base. I have many tridents from Lone Pine, and this is the conclusion I have come to with most of them. Your tree is nice, and could be VERY nice with some wiring and a couple season's good growth (with lots of fertilizer using the technique described above and in my thread). However, the tree could be FANTASTIC with a more drastic course of training including a layer (for good roots and base), large branches removed and regrown (more balanced overall look), and lots and lots of fertilizing/wiring/defoliating/pruning.
Sorry if this is overwhelming, and obviously more than you asked for... It would probably help you if you joined a club. REBS is a good one with a great teacher;
http://www.rebsbonsai.org/
My tree;
http://bonsainut.com/forums/showthread.php?t=3974
Layering;
http://www.bonsai4me.com/AdvTech/ATLayering.html