I used to play EVE years ago. There's an absurd amount going on, tactically and strategically, in these battles which isn't really visible just from a video play back.
As another poster pointed out, formations don't really play any part in things, so everything will just appear to be a big mishmash. But within the two opposing fleets, you'll have dozens of different groups with different tasks. You'll have your capital ships and largest sub-caps duking it out- if the whole fleet's big hitters coordinate and focus on a single target at a time, that target will not last more than a dozen or so (realtime) seconds. Each ship that is targeted will probably try and warp away and escape before it can be destroyed, where it can repair and rejoin the fight. There will be ships tasked with repairing and shield-boosting other ships- mostly in the battle (to "tank" a targeted ship), or stationed at a retreat point (to repair escapees). Other ships will be "warp jammers", to try to stop targets escaping. Others will have "electronic warfare" equipment, and will be coordinating to try to break targeting locks of either the big-hitters or any other class of ships (jammers, repairers, other ECM ships). Then there will be specialist hunter-killer ships designed specifically to take out these smaller support ships. And THOSE hunter-killer ships will themselves be targets of other hunter-killers. And that's just the tactical bit.
Strategically, you'll have fleets jumping from system to system, trying to ambush each other, blockade "warp gates", cut off reinforcement lines or escape routes, fleets pulling off feints and double bluffs.
It's all hideously complicated.
As others have pointed out, it's often more fun to talk about EVE than it is to actually play it. It is a game which is hugely about the meta-game, more than it's about actually flying your internet spaceship. It's possible to get quite a large portion of the fun of EVE Online without ever actually logging in and playing. All the planning of these battles will have taken place in internet forums outside of the game, and the actual battles will probably be being commanded via Skype and IRC as much as via in-game channels.