When you say curved outwards, I assume your mean it has a slight 'hump'.
Well, it's all about fretboard radius.
Your fretboard radius determines how low your action can be while still being able to bend the first and second string without 'bottoming' out i.e a dead note that has 'fretted out'.
To quote an example, the vintage Fenders usually have a 7 1/4" radius while the Gibsons with a 12" measurement. Simply put, the more exaggerated Fender radius follows the hand's natural curve and facilitates barre chords. However, the same tight curve may cause the aforementioned problems when the bent strings run into the slope of the fretboard, hence, 'bottoming' out.
To digress a bit, many Fenders today have a flatter radius but the vintage replicas still retain the 7 1/4" radius.
On the contrary, Gibson's 12" radius has always facilitated bending with no 'bottoming' out, even with very low action.
So you can reference your LTD to my example of the vintage Fenders, and the flatter wizard neck to the Gibsons' 12" radius.
It is all about preference. But I hope my reply has helped you better understand the reasoning behind some of these specifications.