Yo! Been a long time since I've really been doing much with regards to Hawken, so I'll try keep this simple and sweet.
Last time I played siege with full teams and quality players, much of the collecting energy phase of the game had very little interaction between teams. By this I mean, as soon as the game starts, teams would run out to the energy nodes and whichever node had more of the same team would be "claimed" by that team and until the AA phase, no one really would die. My simple suggestion to counteract this is to have one of the nodes put out less energy per tick, and have something in the ui to signify this.
This does one major thing (in theory), make the teams fight over a node rather than just ignore each other. The "weaker" players (less experienced/skilled) can still go to the small node to help out, but the better players can fight over the large node. And to balance things out a bit, have it be random for a certain duration of time. The same node can be selected (randomly) multiple times, so it's not just a flipping back and forth, and the duration should also be a random time (with in a range of course). I think this may be helpful to keeping it interesting when not in the AA phase.
As stated, it's been a while since I've even talked in the community, and I haven't played much recently, so this may be a bad idea for the current meta, if there even is one right now, but it'd be a simple thing to do {a few timers, change a value on the nodes, add a ui element to show which is more powerful}, and may change things up quite a bit.
That is all. (and just to note :P For me this is pretty short)