portage packages should NEVER install to /usr/local. The symlink stuff should also work out if you place the symlinks, beside that you should add a note about adding the ldpreload-stuff to /etc/env.d.
dont care that much feel free to change the ebuild to fit into your scheme of /usr and add the ld preload info yourself
upstream wants it that way. IMO it makes sense but you are free to change the build or ask them to change it if you want it changed.
Ebuilds should never install to /usr/local even if upstream think otherwise -- please fix this properly.
bah if you insist. fixed this and broke all current users and instructions.