Probably your best bet nowadays is the SWiki "class consideration" page: pso2x.swiki.jp (translated). It has discussion of multiple builds for each class and links to skill trees on a skill simulator (note that Google translate seems to make the skill simulator flaky). SWiki in general is probably one of the most well-kept up-to-date PSO2 resources out there.

You can also try the in-game recommended builds available at the class counter, but I have never been brave enough to try them. Also they only work for main class and aren't really set up for a subclass build.