I have a few simple suggestions that can be implemented easily

A "faction loyalty" bonus of sorts for XP and/or steel for playing a Hero from your faction. It'll give being part of a faction more purpose and weight. and make people feel part of an army. Its hard to feel like part of the Samurai army when you play a warlord.

Bump up the bots to level 3 in the 4v4 if not across all modes. I'm sure my fellow warriors will agree that we can handle level 2 bots on a regular basis and are more of a hindrance than help.

Punish quitters. Not dc's but if somebody goes to the menu and selects "quit match" and leaves their team out to dry give them like 5 minute unable to play penalty then racks up for each offense during the day like other competitive games do. higher level bots will also help out the teams who had quitters.