Hearthpwn

dude, this is not an aggro deck, change your descriptions and title, appart from that : 

1) You should alway roll with 2 Mysterious Challenger (Dr.6), yes the second one has less value, but that is not the point, the point is to draw it before/at turn 6 because a) it's a huge tempo gain b) your opponent has a suboptimal turn 7 c) you slim your deck from all the secrets making the topdecks better cards (value wise)

2) this is not based on my math , but it is quite true based on my personal experience that Dr.6 is not (arguably) worse than other six drops when it puts up 3 or less secrets. In short you should either add more secrets in your deck or remove them as well as the challenger and add a better six drop (based on your controlish deck justicar should be a find addittion)

3) Lay on hands cannot imo conpensate for your whole card draw, it is 1/30 to draw and you can't even play the cards the same turn.

TL;DR: get 2 Dr.6's or drop them and the secrets alltogether , add some card draw mechanics.