Here is the problem.
The game you are referencing Became essentially a completely different game after 2007. Same regions yes, but They added abilities, added more items, and revamped much of the existing game.
The new classic game coming out soon had minor changes throughout, but pretty much all changes happen on an expansion basis, giving a solid place to start and stop with what is considered classic.
League of Legends on the other hand. This game evolved slowly over time with only 2-3 seasons creating massive changes. while every other season was slow changes to the state of the game. and with the game being a constant state of unbalance with things being permabanned and other things being unplayably weak its a balancing act to balance. now sure if they released a classic variant and spent 3 years without changes and just buffing and nerfing they might be able to bring a version of the game into a completely balanced state. but the question remains to be asked. What is old school to you?
Is it Season 1? Season 2? Season 3? Those were the seasons on the old map. Season 3 was the season jungle became a fully identified role.
How about Season 4? its the new map and it has all of its interesting jungle mechanics.
Classic means something different to everyone based on when they started playing the game. And honestly. League was pretty fucking garbage in the past. It had high points most definitely, but the game has come so much further. I don't think I could play S3 League anymore. I'd lose my mind. All the QOL changes, the Jungle design is so much better. The Dragon changes improved the game significantly because it gave a real objective outside of 500g.
I think you are looking at the game through rose-tinted glasses for the game in the past / hung up on a champ that got improved drastically with the changes. sure I cant play Akali jungle anymore cause the E got changed, but I identify outside of my niche playstyle the champ got improved. I used to play a ton of Viktor and Loved Augment Death. That shit was the bomb. Oh, Yasuo is about to get his shield? laser his ass so the DOT pops his shield. But the changes to Viktor while they changed his playstyle because of the new augment system, It was a huge improvement. Same with Swain the champ I got my first Penta on. The new swain, while I don't enjoy him as much, is a drastically better champ.
