People posting here (gearheads probably with 15 years worth of L lenses) really aren't the target market for this lens.
As a general walkabout lens with macro capabilities which will be good enough for many hobbyists this lens makes a lot of sense compared to the 24-105. Its sharper, has less distortion, hybrid IS and means people don't need to invest a separate macro lens. For someone moving up from a rebel to a 6D this lens would be great. For those who already have the 24-70 f2.8 mark i or ii or the 24-105 along with the 100L or another dedicated macro lens this offers very little unless you really want a two lens setup to go on holiday and take lots of macro pics. A 24-70 (with macro) + 70-200 is a lot more versatile, and will probably get better images than a 24-105 and 100L.
As with other lenses the price will drop in a few months time (see the 24-70 f2.8 mark ii as a reference).