Yeah, finally played some 4v4 Siege this weekend and I didn't think it was as fun as 5v5. It's one notch too far in to "serious" territory whereas I'd rather it be more crazy like Assault.
"Crazy" assault seemed like the launch party event (MOTD) where picks were made manually and unrestricted.
Regular assault can bog down into a staring match rather easily and drag out for nearly an hour as a result. It just depends on the picks and how much healing vs CC there is. Ra and hell showing up with little to no CC on both sides led to extremely short engagement periods and longer periods of waiting for the 1-2 healers to top everyone off. I'd rather play anything else where at least something is happening.