At the extreme risk of spending all of this time to create a post that is sure to bring about cries of TL;DR, I am going to propose a spin-off idea of yours. My idea doesn't involve the "flags switch the grunts' path" feature, but it does some cool things with your multiple gate idea.
an idea that might make more sense (even for the changing paths issue) might be for 2 more portals to become active once all the flags are held so that you now double you forces on each side with only one of them advancing down the middle. any other ideas?
That is closer to what I had in mind. What if we were to change things around a bit...
(Please excuse my MSPaint mess... my real computer was recently fried.)
- Red team grunt pathing identical to Blue. Not displayed in order to clear up the diagram a bit.
- The Violet circle in the middle of the gated complex must be of some significance that it is to be worth fighting over, but it cannot be so powerful that it absolutely dooms the team on the business end of the effect to lose. I am thinking that a strong experience buff or a valor flag might be appropriate. Perhaps a neutral artifact shop could be placed in the center as well, to increase late game interest in the real estate.
- The center gates (2 & 5) are CLOSED by default. The rest begin in an OPEN state.
- The flags each control a gate as so--
D controls 1
C controls 3
A controls 6
B controls 4
How exactly that flag controls the gate is determined by which team controls the flag. This is where shit gets really confusing, but it makes sense if you take a minute to piece it all together.
In plain english: Controlling one of "Your team's" flags (the flags closest to your base) will CLOSE the gate into the center area on that path for your opponent. Controlling one of "the other team's" flags will OPEN the gate on that path closest to your base.
Broken down by the example labels: For the Blue team, controlling flag D or C will CLOSE gates 1 or 3. Controlling A or B will OPEN 6 or 4.
What this means: Due to the map layout (and supported by tower placement), we assume that Blue will naturally hold C & D for the majority of the match while Red should be able to hold A & B. This will result in the 'normal' game state including a completely locked-down middle section of the map.
The fun part: What do you do in the beginning of the match? Remember that all but the middle gates begin OPEN. Do you rush to cap the flags on your side of the map to close off your opponent's access to the center? Do you rush towards the center, hoping that you can beat the cap and claim the flag in the center for your team while leaving your opponent's path open? This maneouver will require teamwork. The teams will need to decide how much firepower they want to commit to the initial DG v. DG battle to control the middle flag and how quickly they want to close the gates down. This whole early game blitz will require many aspects of the map to be tested very thoroughly. The distances from the spawn points to the center of the map... and to the flags will need to be perectly laid out. In general, it should be quicker to get to a side's gate-closing lag than to run past the gate from the other side. This would make running a gamut for the middle in the beginning a fairly risky endeavor.
This would lead to an interesting mechanic of setting up assault missions to send a DG in for a brief cap-and-teleport-out technique so that an ally can sneak into the locked-down goodies in the middle. There would also have to be some sort of teleport system to allow DGs stranded in the center to return to their base at will.
The middle gates: If a team controls BOTH of the opponent's flags simultaneously, the opposing team's middle gate is opened. This would leave that team in an incredibly dicey situation as it allows direct access to their sole portals. There are no or few towers in this middle section between the center and the back side of the portals. Once that gate opens, a DG can run in and cap both portals at the same time, sending waves of creeps to march directly to the opposing citadel with only some nominal static defense in their way. Basically, if a team with giants grabs both of their opponents' flags... and has a DG in position to cap the portals, it is basically GG. Depending on tower placement and the exact details of the map, I see this happening VERY rarely... and probably only in occasions that involve huge skill discreprancies between the teams. But the threat is always there, and teams must play accordingly.
Both the struggle for the center flag and the management of the middle gates may prove to be too complex or too technical for this kind of game. However, I think that maps like these- which introduce their own gameplay mechanics- would be an interesting addition to Demigod.
It is quite a bit different than your original idea, but the inspirations are similar.