What's wrong with aiming for certain natures, EV spreads, and IVs on pokemon? How is that "stop having fun guys"? For me, I love seeing high stats so I go out of my way to make my pokemon have as high stats as possible (even if I never use that pokemon in a single PvP battle). Only if I plan on battling competitively do I go for the "perfect" EV spreads but often I like to max HP in EVs because I love having a Pokemon with high HP.
Sweepers (high SPD + ATK/SP. ATK) are actually super common. I think it was Gen V that made defensive pokemon not as viable because they made sweepers soooo dangerous. And there's the Psyshock move, that prevents a Blissey from walling something like an Alakazam. I'm not sure yet how defensive pokemon stand with new additions in Gen VI.
Charizard takes only 25% damage from grass type attacks....I only see a Charizard taking 90% damage from a Giga Drain if he was 30 levels below you. Plus Torterra has poor Sp ATK. I don't mean to be a spoil sport or anything - I'm just commenting on an example that screams "hyperbole".

Weaknesses/resistances are a huge reason you can defeat a Pokemon that's 10+ levels above you. Charizard is 4x weak to Rock, for example. He also has weak DEF stat. Something that can resist Charizard's attack options and then whip out a Rock Slide could destroy Charizard in one move. Likewise, a pokemon that's 10 levels over Charizard that tries to attack him with Grass (dealing 0.25 damage to him) will likely get destroyed (and Charizard's STAB moves like Flamethrower will do 2x damage to Grass Pokemon anyways).
Goodra is probably my favourite pokemon from Gen VI (aesthetically) and it's Base Stats suggest Special Tank/Wall. But I'll probably build it with Sp ATK and SPD EVs anyways because that's good enough for normal play. It's a shame that Noivern's stats seem so poor because he looks pretty awesome, too. My team for the main game was: Delphox, Tyrantrum (<3), Doublade (didn't want to evolve him), Pangoro, Talonflame, and Florges. I'll get a Goodra once I'm ready to start doing some breeding to get good IVs for it.
There are so many ways you can build a Pokemon and part of that is why I get so absorbed in Pokemon games. I think it was discovering the existence of EVs and IVs that actually sucked me in for the long road. Being able to increase the stats of a Pokemon beyond their "natural" means in any way/combination you want (within a certain limit of course) is extremely addicting for me.