Will Summer Sale deals be on Bundle List?

sleeping dogs was 91% off and it's not on the bundle list

No it's not. The games has to be in the bundle or be exploited to be on the bundle list.

let me explain difference between lets say 50-75% sale on steam sale and lets say 98% sale as part of a bundle:

It may seem that the difference may be 23-48% so 1/4-1/2 max, but "purchase prospect" is much higher. Lets say you have 10$ in your wallet. The game you want to buy costs 10$ and goes on sale. If sale is 50% off, the new price is 5$, you can buy 2 games, so it's 100% more than normally. If sale is 75% you may buy 4 such games with your 10$, so you can buy 300% more. If game becomes avaiable in bundle with 4 other titles for 1$ minimum, the cost of a single game from the bundle is actually ~0.2$ average which is 98% price cut for this particular game. Considering this one game only with your 10$ you can buy 50 copies of this game, which is 4900% more games than normally, and 49 times more than in 50% sale and 16.(3) times more than in 75% sale.

There's a huge difference between 66, 75 or ever 80% sale and 5 games bundle for 1$.