The point of the final kanto evos was to be specifically NOT what would be natural progressions, but a subversion of expectations. And their iconic status came from the fact the game ushered in a new era of human culture - that of pre-pokénon and the cuirrent post-revolution era, not that the fatfuck flying lizzer was good, beyond being exactly the kind of shit that attracts 7 year old boys (which is why 'Zard is still popular today, 'toise and 'saur are still the runners-up).
The natural evolution of the series however was always going to be default to humanoid - humans relate better to things that look like them (which is why Fuecoco mogged Skeledirge but Meow mogged everything that wasn't excessively kawaii). Sorry how they sold the kiddy toy to you as a youngfuck isn't how kids today accept their media, I guess. But that's what happens when a kiddy media keeps focus on kids, instead of drifting to spergy manchildren, before re-assessing their target demographic, like Star Wars did.
