Skill is oddly worded. An 1.5x increase in Attack Speed should be him at 1.13 Attack Speed at level 1. Instead, what it does is take 50% of his attacks speed, then subtracts that from his total, giving him 0.85 Attack Speed, which is actually twice as fast, not 1.5x.
At a 5% increase per Skill Level, if Wrecker kept following this formula all the way to level 10, he would hit 0 Attack Speed and have infinite attack speed at level 11.