I can't help but feel like this will result in worse discounts, which is (sort of) a bad thing. The excitement of a 90% discount that was only good for a few hours - Buy now! - now gets replaced by the need to only check the sales once, and be done with it. I've made a lot of impulse buys on flash sales over the past few years. (Some of them I've even played).
On the other hand, flash sales had upped expectations too high, perhaps. I know this past summer sale, people were complaining about the "merely" 50% and 66% off titles. Without the random 90% titles thrown in there as reminders, people may be more willing to accept the lesser discount.
On the gripping hand, publishers still seem to be keeping PC/digital prices artificially high. Take Lords of the Fallen, for example. It is still $49.99 for the base game on Steam. The PS4 Complete Edition, with all the DLC, is $29.99 MSRP. You need a 40% discount just to get to the console MSRP! When publishers are doing pricing tricks like that, it makes sense for consumers to demand 66% or 75% off sales.
Honestly, half of my excitement for any of Steam's seasonal sales is for the gimmick. Gambling on last year's gem market, or this Summer's Wormholing (I got my badge!), are almost as much fun as finding a really good deal on a game (over a merely good deal). In any case, Steam has pretty solidly established itself, so I doubt they have much to fear from this change.