I like the idea of Alliance Battles giving you rewards, but not necessarily in the way you suggested.
What if:
* There was an Alliance Battle ladder? This could be worked out by the number of wins per battles played. Since most of the time you party with random people (and have almost no control over the other two teams on your side), the ladder could be per person, instead of per team. At the end of the day/week/month/season the top few players would get a reward item, almost like the loot from the chest in HoH
* For the fun of it (if possible), a leaderboard for the most amount of faction transfered by each person. This could display the the top 100 or so players and show how much Luxon/Kurzick faction they've transfered. I've always wondered if someone has the Saviour of Luxons/Kurzicks (though someone told me they saw on the other day O.O)
* It would be nice if controlling enemy territory had more of an impact. Currently the NPCs are changed to the opposing faction, which only prevent trade and such from taking place. I'm not sure on how this could be implemented, but it would be nice. Maybe certain special quests would trigger for the faction in control of the enemy faction's territory, thus impacing the PvE aspect of the game more (like wins in HoH gives the Favour of the gods to PvE players)
* What would be fun is if at the end of the month or whenever, players at the top of the leaderboard could participate in "high-ranked" alliance battles, in which the aim would not be to capture the shrine but to capture the enemy territory or such. I know I would want to AB more just to be able to experience this "elite" section of AB. Winners here could receive rewards in the form of weapons etc.
* Lastly, this is more of a suggestion than a reward, but it would kind of be a nice reward to players. New maps please. I can't express how frustrating it is having to play on the same map over and OVER again (Grenz Frontier anyone?)! Maybe if there was a substitute map for each "level" of enemy territory owned. So instead of going to Grenz Frontier when the Luxons have won more battles that the Kurzicks, athey could possible go to an alternate map. Which map would be truly random. Instead of players waiting at the actual map to enter battle, they could travel to a special "waiting area" where they then click enter battle and get placed onto a random map with other players. This will eliminate the chance of players getting spawned on different maps in the middle of the night when there are just enough for one battle
So yeah, that's just my two cents

I enjoy AB and hope to see the support of others. Due to the fact that so many ABs happen within the course of the day, weapons couldn't be offered for every win, but the above strategy I think would be fun and would reward those who spend time playing