Now that Gnats3 has provided some awesome info on the flag numbers, ( http://www.gamereplays.org/demigod/portals.php?show=page&name=tip- of-the-week-demigod-flags ) it is time for some map feedback, starting with prison.
First thing that comes to mind is how lopsided prison is. On one side you have a goldmine and the artifact shop, on the other side you have an exp flag, and in the middle you have a celerity flag. The value of the experience flag seems to be the weakest. I would rather have a gold mine than an exp flag. Yes, 10% exp bonus is nice, but in the start it isn't a huge deal. Overall the feel I get from prison is that the flags are on the weak side in general and it favors ranged gods due to its small size. They can retreat back further and use their towers, while melee gods have a more difficult time pushing into these towers and capitalizing on defensive positions. Kiting is huge on this map and melee heroes also have a difficult time putting some hurt on the enemy before they get to their allies or their allies arrive to help them. All in all, melee heroes have to put themselves at risk to get things done, while ranged heroes do not have to do this, plus there is little reward for the area control which melee players achieve.
My first thought is that both sides need a gold mine, the far side flags (item shop and exp) really need to have similar values. In fact, it would probably be best if the item shop was moved to dead center of the map with both of the outer flags being converted into gold mine+exp flag. The center flag also needs to be more powerful. Converting it into a rejuv or regen flag should really reward the team that holds onto the center. Celerity just isn't that valuable when most cooldowns are 10s or less. Mana tends to be more a limiting factor than cooldown.
Finally, I think the map needs blown up, slightly. A big more distance between bases and between the sides could give melee a more room to work with before the ranged heroes hit their tower wall. Loosening up the first tower network that the grunts hit could help this a bit too. It feels like you can't even scratch the enemy base early on. I am not talking about drastic changes, but travel time between sides and bases can give melee gods a little more time to hammer at a ranged hero before he runs back to heal. Currently a ranged hero is to safety in the blink of an eye and will be healed up an back in a flash. They simply don't feel the penalty for being forced out of a lane that they do on other maps.
All in all, I think the map needs to be a bit less friendly to a defensive strategy. Currently, all you have to do it try to grab the gold mine here and there.