Riot Games outlined their plans to fix the League of Legends client so it's not the sluggish disaster it is today. Through focusing on fixing two things, the team hopes they will fix loading and champion lock in times as well as any bugs on the way.
League of Legends' client is undoubtedly the weakest part of the game and it seems like Riot Games have had it with this link. They recently announced the Client Cleanup Campaign (CCC) which will focus on fixing bootstrap and champion select lag. The official post claims that fixing these should also deal with many bugs in the process.
Regarding the bootstrap, it is the time the client needs to load up initially. According to CCC announcement, the team is trying to make the loading time be shorter than 15 seconds, even for the players with slower machines. Unfortunately, the current times are nowhere near that goal as it normally takes up to 45 seconds or even up to a minute currently.
The other time saver the developers are looking into is the champion select. This one does not directly pertain to saving time from the point of not playing to the point of spawning in the fountain but it can have more serious repercussions. Currently, only 20 per cent players have the lag of 200 milliseconds from picking a champion to the game registering it.
While this might look terrible, the other players have it worse. The bottom 20 per cent of players' champion lock-in delay is between ~550 ms and 1800 ms, with a small percentage going as far as 2400 ms. In other words, the vast majority of players have half a second to 1.8s lag in champion lock-in.
Besides being an inconvenience, this presents problems in a draft pick when the players may try to counter the enemy team but their time to strategise is cut by the lag.
Addressing the bloated number of plugins and Ember apps will deal with both of these issues and the team hopes they will stumble upon client bugs that they can fix "opportunistically" along the way.