I've played the map and would like to weigh in now. I'd like to say first off that I've never really cared much for unit rebalancing acts or mods that go above and beyond with custom unit stats. I've also not been able to play this against another strategic human being, nor have I accumulated many hours experiencing each possible nuance or situation, so you can take my review with a grain of salt if you so please.
The Heroes
Starting with all eight heroes is fine, but it introduces the problem when maps like Doubles start too close to each other. You know in SBS if you lose Sarge you can consider yourself dead. Well this is only x8 now that all heroes are involved. Especially Bullseye, who is a sniper unit. It creates the situation where Bullseye hard counters all other heroes and creates a sort of stalemate.
Secondly, the hero type armor is extremely OP. Heroes simply don't die. Ever. I've found I can assault a base to no end, and without at least 4 expensive snipers in tow my efforts are for naught, since a big clump of hero units will simply squash even tanks. Sarge and Vikki's range doesn't help that they barely have to move from front lines to take out the snipers shooting them, the same snipers who take almost 10 shots to bring down Sarge.
The Resources
I have not played the Eight Train map, but the Doubles map seems to have a severe lack of electricity lying around. I found myself and my foes quickly spent out on useless vehicle units. I think there should either be more electric around, or maybe a garden lamp instead of the not very valuable Captain Dans in the center.
Minesweepers
Have you reduced their movement speed? I already had trouble with them falling behind in vanilla gameplay, and now they seem to be even slower. I found even my tanks running over mines because my sweeper was behind. And even when they are placed out in front, because they move slower, they will eventually get bumped from behind, which causes them to sidestep and fall back behind again.
Random Target Style
I want to go and say that I did not enjoy this at all. If two armies were to clash head-on and fight to the death, then Random would be effective. This is not the case however, as units tend to bunch together, move in straight lines, and take obfuscated paths. This can result in poor matchups where faster weak units meet with strong vehicles, and thanks to the Random target style not allowing retargeting, then you will usually find the high health units targeted first, resulting in the first army picking off units quickly while the second continues to focus on the stronger units. You could make an argument about micro managing your army or units, but this becomes less feasible or even simply impossible when multiple factions are engaged, or you are assaulting multiple fronts or defending your base. Furthermore, I think the exploit of using the terminator AI to lure aggressive units into an ambush is not very good design, nor is it fun to play against especially online with latency. I think if you wanted an effect of where units don't waste time picking the lowest health at each step, then I would have a suggestion:
Why not have splash damage units, or artillery units like Grenadiers, Tanks, and Snipers use the target style of "MaxDefense" so that they will only target the strongest opponent. Then you can have the single shot units like Grunts and Half-Tracks use the default aiming style to finish off the low health units. Sure this can be countered by careful spacing, but I feel it would be better than the current situation.
Unit Limit
Not all negative review. I found the unit limit to be nicely made, and while I never hit it ingame, I can definitely support the idea if varying degrees of unit costs. Although I will say that with other changes made, the Tank does not nearly deserve it's four unit cost in this environment. I found the Tank to be severely lacking from it's vanilla standing.
Unit Changes
Once more, I have not been able to compete with another human player, nor have I used each unit in each situation, but some changes I did find very notable.
- Grunt - I found the grunt to be entirely worthless. Their range is too short, so they often target one enemy, then have that enemy move out of range. Unfortunately, unlike vanilla game, the Random target style prevents them from simply retargeting, and they will instead opt to pursue their target into danger. Combined with their low health, Grunts fail in almost every aspect, as even the Grenadier is cost effective.
- Tank - As mentioned earlier, the tank has been vastly downgraded from vanilla. This isn't a bad thing, but I found them to be a bit extreme. They suffer the worst from the Random target style, since when their target runs, their turning and movement speeds are so slow making pursuit even worse. Their damage output I found to me mediocre against buildings, and their health doesn't seem to be as good anymore, I frequently found my tank squadrons easily defeated by machine gunners and half-tracks.
- DumDum - Wow. The dumdum is ridiculous. Their range is insane now, and they aren't any more expensive from vanilla. On top of that, they little unit limit. With the large amount of starting plastic, I can see it being a very dominant or even overwhelming strategy to get even a few dumdums as early as possible to push into the enemy base. Their low health doesn't even stop them, thanks to the Random target style, since you can use a sponge unit to take the hits instead, which can only be beaten by manually targeting dumdums.
If these points I've made can be addressed, I would be glad to play an updated version of this map. But as it stands now, I believe it's a fine map to play, and one that is very creative in it's unit cast. Be that as it may, it is not a map I would wish to play.