Even in 1.12 AV if both sides want to win long games will happen. It wont go on for days like in 1.5 but that was largely due to all the NPC’s with high hp / dmg slowing things down.
Also there won’t be any zerging in 1.12 either due to many things like slower movement speeds in general, longer recovery times, longer respawn timers, and healers not being god mode all make the modern zerging of AV not possible.