bot tower so weak

Bottom tower is intentionally weaker because it is meant to be a more sought after objective.

It also has two champions defending it.

It is balanced because it is the same on both sides.

Its only weaker for the first 5 or so minutes.

Also, mages do not go bot to outpush ADCs.

Only Ziggs goes bot.

The simple fact that there are typically two champions in the bottom lane makes the lanes "unbalanced."

That isn't the point, if you have both teams focus on the same part of the map, they are just as likely to apply equal pressure to that side.

The problem was that before they did this, which ever team was losing the bottom lane early on would lane swap with top and press down that tower while they lost the bottom tower.

That lead to a trade of objectives instead of defending / contesting objectives.