Winger toward middle
A player who's positioned at a winger slot with the individual order of towards middle. Most often used with pure playmakers, but a high winger skill still contributes towards the wing attack.
Mostly PM and stamina are required. Passing is always helpful for any midfield position. Winger is still used, but not nearly as much. Defense is always slightly helpful as well.
Basically, a WTM should be an IM that you would play normal since both his defence and passing comes into play somewhat.
WTM and Winger Special Events
Wingers Towards Middle are still Wingers, therefore they can benefit from Winger SEs.
From the rules: Wingers with sufficient winger skill can create chances that will have to be finished off by another winger or a forward. If that other player is a head specialist or has sufficient scoring skill, he will score.
How much wing skill is "sufficient" is up for debate. However, WTMs with very modest wing have been known to generate WTMs. There is no clear evidence that high wing skill generates more Winger SEs.
WTM plus FTW
If you are planning on playing a Forward Towards Wing (with high wing skill)in front of your WTM, then some wing can help the wing attack a bit. If not, then don't bother with the wing skill part.