Indeed the classical varieties provide more desirable and balanced effects like mental clarity & lucidity, mainly thanks to lower THC levels and more varied cannabinoid & terpene profiles. Classically THC was at ~5–15%, with CBD, CBG + stimulating terpenes. Thesedays THC is at 20+% with low/zero CBD/CBG... thanks to commercialisation re introduction of shorter flowering genetics and focus on higher THC %.
@LucH
Looking at THC alone and making broad conclusions doesn't give an accurate picture of things. There's a complex entourage effect going on between numerous pharmacologically active substances eg cannabinoids (CBD, CBG, THCV) and terpenoids (which are common constituents of plant essential oils eg limonene, linalool, pinene, myrcene). Aromatherapy...
CBD acts to balance THC.
CBG is an α2A agonist which reduces adrenaline and is pro-GABA.
Cannabis terpenes are valuable too... pro-metabolic (phytol), pro-dopamine, anti-cortisol, anti-serotonin (limonene), pro-GABA (linalool), pro-BDNF (beta-caryophyllene).
A seed company called ACE seeds carries many classic "sativa" tropical cannabis genetics, here's the description for one:
Clean, energetic, all in the head 'Feel good!' sativa effect of moderate strength and duration, without ceiling, tiredness in the body or hangover.