Hmm ... Does optimizing in the original Final Fantasy count? I was 10 when the game came out, and my second playthrough I built a party of 2 red mages, a white mage, and a black mage. Sure, it took some coin farming to afford all the spells and gear (possibly the most expensive party to fund until endgame where gp doesn't matter anymore, due to good gear only coming from chests) but I had spells for any situation and enough to get me through just about any dungeon.
As for D&D, I was playing with bladesingers and battleragers (Thibbledorf Pwent was a good character model), RAWing rules for ranger 2-weapon fighting (bastard sword and club? Why not!) and using Wild Mages, especially because I knew my DMs could not resist the siren's call of the Deck of Many Things. All in 2nd ed.