Please don't forget about significant amount of pub-server players, who doesn't know how the game should be played, and get wiped every time on wave 6 or 7. They have seen Patriarch only on screenshots, or when they were playing on Beginner. Bringing big zeds too early will ruin clot-killing fun for such players

Another aspect - getting wiped on later waves now is more painful, because it means another half an hour spending on early waves again. Shortening game too much will decrease suffering effect for getting wiped - team just can restart the game and get into the action really fast.
But I must accept that Long game is too damn long. Especially wave 8, that is even less challenging than wave 7.
So I'm suggesting to give achievements for completing Medium game too, and alter it to this:
Wave 1: Same as it is now +
Stalkers and
Crawlers on Sui/HoE (because level 5 and 6 players spawn with initial weapons).
Wave 2: Introducing both
Husks and
Sirens
Wave 3 should start with
single Scrake spawn (like Long game's wave 7 starts with FP), so team can test its Scrake-killing abilities. It is good for pub games, where team must ensure that designed Scrake killers (SS, Zerker, Demo with LAW etc.) know how to do their job. A few more Scrakes during the wave.
Wave 4 should start with
single FP spawn (wave 7 in Long) for the same purposes described above, and a lot of Scrakes during the wave.
Wave 5:
Single Fleshpounds spawns together with another big zeds (Sirens, Husks, Scrakes).
Wave 6:
Double Fleshpound spawn.
Wave 7:
Tripple Fleshpound spawn should be a rule for Sui/HoE, not the rare exception. And possibility to get spawn of 4 Fleshpounds in the group on HoE.