Honestly, the best part about the zerg is BSing with random players, it's also the worst part in some cases.
The renown gains are terrible, once I hit 26 and started roaming with a small group, (on most occasions, not even a full 6 man) renown ranks came much faster.
I understand everyone wants to be at every BO for the tick, but it seems much more rewarding and clever to send a 6 man to each BO, (that's 1 full warband for those that can't maths.) then have overflow, be it just another 6 man to a full warband, sit at the opposing keep to stop would be defenders from entering.
This format would accomplish quite a few problems that we see with the zerg.
Fun. This is what we are all here to try to do, riding your mount from point A to B to C to D to E isn't.
Fighting is, with a small group per BO gives the opposing side more of a probability of coming to defend it, Giving you a fun fight, Freenown, and dare I say, feeling as though you were a contribution to your realm, which leads me to my next point.
Knowledge of your class and others. riding the Renown-O-Coaster usually leads to knowing very little about your class, most of us are vet's to WaR, but even so, we like to play a class we've never touched, be it in live or RoR. The small groupings, as proposed, would give players the chance to gain experience with their class, beyond the knowledge of where their mount keybinding is.
We've all done it, been standing next to someone, health slowly ticking away, hoping for a heal, a punt/knockdown/guard, or a little more DPS on your soon to be murderer, but it doesn't come, are they bad?, or just have the zerg-mentality?
when zergs collide it can be messy, very messy, people never know who is hitting them, and with what. do you cleanse the Boiling-Blood, or the armor debuff? Beat on the tanks or go for their dps or heals?
if you have an answer, you're wrong!

WaR is subjective, to quote Sun Tzu: "If you know the enemy and know yourself, you need not fear the result of a hundred battles."
Knowing the enemy, class mechanics, as well as their personal play style, can lead to amazing victories, small groupings gives your realm a chance to learn these things.
Even if you know the ins and outs of every class, you can still learn the players, learn who to focus, and who to ignore, who is good at their class, and who is bad.
Side note, This is less of a rant and more food for thought. I see both sides raging about PuG's, but little is said about how to improve their play, if you see potential in someone, pull them into a group when you are a man down, give them pointers, and go roaming. The worse that can happen is you have to respawn.
Cya in gaem nurds <3