This is 2 topics in 1

Firstly, i would love to know when to build crit vs when to build armour pen (ghostblade, duskblade etc.) As Adc.. thanks.

Secondly, i have a gameplay idea i think would be super fun. 1v5 - on Howling Abyss: 6 players join a lobby, one of them is randomly chosen to face the other 5. The solo player is level 18 and has unlimited gold. The other 5 players start as normal and must work together to stall and farm long enough to ramp up and overcome the level 18 solo player.... obviously there will be some major balance tweaks and stuff but i think it would be fun, as the solo player must end the game quickly before the others ramp up and outscale him.

What do you all think about this idea? Would love some feedback. Thanks all!