in general, i'd agree with dracon fighter about dual classing. any time i've done it mid-level (ie not 1 level of mage at the beginning, or switching bard to fighter at level 20+) i've been disappointed. but, it's a challenge for me to find a way to make it work, and my nature abhors an unmet challenge
regarding alchemy dual classing, you reminded me of another atlus 7 gem: the ninja-ranger dual (non-faerie). the concept would be to start as a ninja, using dual nunchuck and bow, concentrating on maxing out stealth and critical strike (and l&t if you're solo), including building up alchemy spells. then, when you switch to ranger, you use dual mace (mauler/DE) and bow.
the key benefits are that you would have the ninja's stealth ability to boost the ranger's AC, you'd have the ninja's critical strike ability added to your ranger's melee, and you'd get the ranger's critical ability for the bow and complete access to ranger armour (ie infinity helm!). not to mention they use the same spellbook (alchemy!)
now that could make an interesting solo, or member of a small (duo/trio) party.