I Actually Don't Mind the Change to Turrets, But...
I think the REAL problem with having turrets without armor is the damage amplification you get from second drag. Before, you could use this to kind of offset the turret's armor. Now, if three people push mid before 15 minutes with two drags, the second tower crumbles to the ground.
I think second drag's bonus should be replaced with something else entirely. It will really help to slow down the snowball of the game. How about if when you take second drag, your team gains a buff that increases bonus armor and MR by 5%?