Let's stop romantacizing Season 2's balance
To say Season 2 was the best season is subjective. It depends on who you ask. I'd personally say season 3 was the best season, but again, that's nothing a fact - it's just a matter of opinion. And any opinion regarding that is totally fine because you are entitled to your own opinion.
But you know what is a fact? Balance is significantly better now than it was in season 2. We often blow out of proportion how great season 2 was because of our nostalgia and the fact that season 2 is when this games popularity really took it up to a new threshold and climaxed. That was an awesome feeling, being a part of gaming history was an awesome and satisfying feeling. But let's stop pretending that season 2 was somehow this magical land of balance where everyone was happy. Let me remind you of a few things..
•Supports legitimately got no gold.
No, seriously. As a support, you bought Philo Stone and HoG and wards with mobis/oracles. That was it. You didn't get any other items. You were considered fed as a support if you managed to complete aegis. You absolutely had to take exhaust, heal or clairvoyance. Any offense summoner was frowned upon. You were absolutely 110% the ADCs bitch with no room to play on your own. While that legacy still exists today, that's largely changed where supports can often have AP (or even AD) carries plugged into it and carry games. This was literally impossible in season 2.
•Junglers were extremely gold starved
Seriously, the jungle of them was extremely harsh. Once again, HoG and farming as little as possible and ganking. You basically played Maokai, Lee Sin, Nunu, Shyvanna, Mundo or Udyr. You legitimately couldn't play anything else or you'd get invaded, die once and be 3-4 levels behind the rest of the game. It was way more feast or famine, to the extreme opposite of what you have no where dying early as a jungler isn't that punishing. Back then, if you died once early as a jungler, your game was over.
•Guys like this were legit nearly 100% banned:

Malphite was legitimately unkillable to an ADC, even with LW he could shrug off those pesky ADCs and murder them. Armor stacking was ridiculous in season 2, anything could stack armor and Ben successful. But it still had some drawbacks because armor stacking left you vulnerable to AP damage. So this balance was decent but Malphite was an exception because of his old W and natural synergy with armor/anti AD items (FH and old Randuins).
If I need to explain s2 Kassadin, you probably didn't play this game in s2.
•Top lane was the Olaf vs Jax vs Irelia featuring Rumble show
Sure, you could play other stuff but if one of the above 3 got picked, you were at a serve disadvantage. Tank tops weren't really a thing other than Maokai. AP tops for nerfed into the ground and FoN existed so double AP was dangerous to run by the end of the season. But at the beginning of the season, double AP was OP and had to be nerfed into the ground. You weren't from one extreme to another. This was common in s2.
•The first ADC to get GA won.
Seriously, it's that simple. ADCs decided the game. You either picked Ez, Corki or Graves. You could not play anything else. You would lose. And whichever one got GA first, they win. And if you did by chance pick something else like Kog, well have fun if you don't beat Kogs team by 20 minutes because he was going to penta kill. But that usually didn't happen.
•Feast and famine gameplay was really the basis of s2.
Season 1 and beta had extremely unhealthy elements like manaburn and minion denial (Gangplank) but most of that was cleaned up by season2. But S2 itself was still extremely feast or famine. If you fell behind back then, you stayed behind pretty far unless you got bailed out. This is only true now because games end so quickly and snowballing is meta because lethality is OP. But that will be balanced and games will feel reasonable again. But in season 2, the games were longer but it was often a tail of one team starving another team to death. And the game hasn't reached that extreme since.
•AD casters were god awful
Not only did they suck, but they had almost no itemization. And because of this, Riot to basically overtune their ratios to ridiculous levels just so they could compete. This is why the BC preseason 3 meta was so extreme because of AD casters being so bad they had to have their numbers overtuned as hell just to function. This was the most severe case of feast or famine. And once you bought a chainvest, you basically ignored AD casters for the rest of the game. There were a few exceptions but this was the general rule.
I could keep going and the legacy of some of these mechanics still exist today but it's not nearly as extreme. Balance and understanding of balance is so much better today than it used to be. Liking and enjoying s2 more is fine, I feel the same way. But the game is by far more balanced now than it used to be.

this monster was created and only the junglers that could keep up were viable.