In my opinion Skill is killing your opponent with 4 BR shots, Getting head shots with a sniper, Using your grenades effectively, Using the map to your advantage, learning tactics (weapon spawn times, spawn locations ETC..)
Skill is not Jet packing to get top map control, its not Armour locking when you've been stuck, its not camping with active camo....
Well atleast from my experience playing halo since the launch of CE, I can imagine that someone that hasn't played halo before and starts playing reach may find it entertaining, but for me its just not halo, I feel it doesn't have the competitiveness of <halo 3.