Or you can just doesn't focus on completing your nexus the day after the patch.
Not every one is aiming at having everything as soon as they are released.
As Nuts says, not every player enjoy rushing 100 times the same thing just to progress faster.
Yeah you get your Nexus faster that way, leaving you with : 1-bored of a part of the game as you ran it untill being disgusted, 2- nothing to do IG untill next patch... It make me think about all those SR in Brayflox HM for having their animus in a few day.
Now, we get far more Myths, and Animus is done faster than before in a less boring way. So player will catch up, as previous content is eased when ilvl rise!
And one last thing: having a 115 weapon is far from being the only way to enjoy the game, you can already be powerfull enough with a 110 weapon, so nah, there is nothing to worry about the Nexus and players being left behind.