Game Mechanic

We had to choose a published game and create a new mechanic for it. I struggled thinking of a game to focus on at first because during the last 3 months, all I've played is LEGO Lord of the Rings for 8 hours a day and forgot what it was like to play other games. I eventually chose Skyrim and thought of 2 ideas for it. One was to shoot a target (not an obvious red and white circle target) and then water or snow (dependant on area) will rush out to quickly remove enemies. I did think the target idea was very Legolas style though in LEGO Lord of the Rings so I chose to use my other mechanic. I noticed there is no climbing ability in Skyrim. Yes you can walk up mountains, but you cannot actually climb anything and I thought this could be an interesting mechanic.

If you could climb, you could get to new areas, camps and caves that have special loot, that you couldn't get to if you can't climb.
You could also quickly escape enemies which would be useful if you were swarmed, eg. in a city if you have commited a crime.
This would also make Thieves Guild and Dark Brotherhood quests easier as you could get to objectives in a different way, hide from people if needed and also escape if you were seen stealing or killing someone.

There could be specifically placed small rocks on rocky walls that you can climb, not making them stand out too much but so they look slightly different so the player knows they are climbable.
Also wooden ladders and ropes hanging from rooftops can be climbable to get to the top of rooftops.

The mechanic could be programmed so that players wearing heavy armour or have low stamina cannot climb or climb very slowly, whereas players wearing light armour and high stamina climb things with ease.