Have an ability to preview skins before purchasing.

http://www.lolking.net/models

Yes

Skin Spotlights too

To put an in client viewer would be to much effort. Just use the lolking or YouTube.

you can always look at them on lolking or youtube. having the ability to look at them in the client would be nice, but is it really worth the trouble?

Yes riot should consider this as an option it will make people fell like riot respects them and their choices