I voted maybe as well. There are a few things you might consider.
Assuming you are looking at a "WP/VP" model; instead of a "more detailed" hp system, why not just change (lower) the number of hp (CON=hp or some such)? If armor absorbs damage, weapon damage is different, and the to-hit rolls are different than straight d20; then lower hp should be all that's required. When in doubt, reduce complexity.
For weapon damage, you may want to look (if you haven't already) at the GURPS "swing/thrust" rules where the weapon modifies the character's base damage instead of vice versa.
You mave have already considered these ideas and discarded them for your own reasons, but I'd thought I'd mention them.