As Relasine has sold off his army, I guess I can give it a shot...
Strategic Analysis - Ogrun Assault Corps
Some say that the arming and training of 'primitive' peoples is a bad idea. When it is a 8' tall Ogrun, armed with what would be a deck gun on a ship, and trained with typical Rhulic professionalism, many would argue that the era of humans on the battlefield is over.
In truth, while the potential for such a unit is great, the reality is rather mediocre. And then, there are the field marshals that the factions get...
The OAC unsurprisingly have a very typical Ogrun statline. Decent speed, massive strength, and of course, eight wounds each. Their armor is rather low compared to most Searforge models, though. But their speed and battlecannon gives Searforge players a unheard-of 18" threat range.
Hand Axe - a decent, though not thrilling hand weapon. On average rolls without a CMA, you'll be throwing out 19 points of damage, more then enough to take down most warrior models or put a dent into a light warjack.
Battlecannon - A decently ranged weapon with a small blast template and decent POW. It would be spectacular if it had a medium template, or slightly longer range. Or had a special rule. But it doesn't. So it falls into the typical Searforge "Solid, not spectacular" paradigm.
Combined Ranged Attack - A very, very important thing to remember: combined attacks add to your damage roll, not your POW. Which means that a full squad of OAC combining will do a POW 12 blast with +5 to the damage rolls, including blasts. Which means that on average, your direct shots will do 24 damage, and blasts will do 18, making even the blasts capable of hurting warcasters, removing shieldwalled units, and even putting a point or two of damage on a heavy warjack.
Combined Melee Attack - Get all your guys in half an inch of the same model, and you can unload a massive hit doing around 26 points of damage at vMAT of 11. The problem being, of course, getting 5 medium-sized models in melee with the same model.
Overall, you'll probably use the CRA a lot more then the CMA. But if you get charged, it's a nice option to have a buddy nearby that will stiffen up your fight.
Battlefield Role -
The problem with the OAC is that while they are good at the things they do, there is very little they do that our other units don't do already, and usually better. While they can soak up damage, with their relatively low ARM and only five models, they actually take less damage then a full squad of High Shields or Forge Guard. Their CMA is impressive, but pales compared to the vPOW 20 of a full squad of High Shields. While they can hit hard in melee, they are nothing compared to the weaponmaster-reach-ranked attacks of the Forge Guard. They can put out 5 blast templates in a round, but Herne & Jonne can do three for a fraction of the cost. And at 9 points, they cost more then either of our main units.
Where the OAC shine is in their versatility. Forge Guard lose out to mobile ranged units. High Shields and Herne & Jonne suffer in melee. While they may not be spectacular compared to our specialists, they can easily step into the place of one should something happen. Your Forge Guard get shot to pieces and you really need some melee done? OAC. Your High Shields get caught up in melee, and you need to make that high-damage shot? OAC. H&J get swatted, and now stealthy models getting in your way? OAC. In some limited tournaments or army lists with only a few points for units, then a OAC can be your 'anything goes' unit. In an army known for their mixed arms units, the OAC are the most mixed.
Due to their good threat range, the OAC should be placed mostly forward. They are surprisingly squishy, though, so over to a side to draw less fire. Their ideal opponent is heavy infantry, especially shieldwalled units, where their blasts will wreck havoc. Multiple templates also mean that they can hunt for Stealthed models as well. They can do surprising assassination attacks, moving relatively quickly and combining into one massive attack. Doing so after Gorten's landslide is almost unfair.
Grouping them in twos and threes will give you a slight boost for combined attacks, while letting you still have multiple shots.
Alternately, keeping them near your warcaster gives you a bodyguard unit that can stop tramplers, and react appropriately to whatever might slip through your main force.
Supporting the Ogrun Assault Corps-
Unfortunately, because of their lack of specialization, there is little that helps them, that wouldn't be better placed elsewhere. Primed can give them a very nice boost, but to melee only. Explosivo only affects one model, and can't be used with a CRA. Solid Ground helps them as much as it helps everything else we have. Because they can drop so many templates, letting them shoot into melee while Solid Ground is up is a valid tactic.
A Bokur can give the unit some nice melee punch, and also shield guard damage letting you keep combined attacks going for much longer. The question being whether driving the cost up to 11 points is worth it.
It's also important to note that Madhammer's feat only affects the blast damage rolls, not the direct. Granted, that means a full CRA does almost as much damage on a blast as a direct hit. And with a ranged attack at +5 (CRA) and 3d6 from the feat, you will hit even the slipperiest of warcasters. But only for that one round.
While you can take up to three in a Searforge force, I find it hard to justify more then a single squad. Yes, they can step into whatever breach opens up, but our specialists are cheaper and better at their individual roles. In theory, you could make a whole army based around them, three squads of OAC under either Grundback or Madhammer would be quite impressive, but I have a hunch that they would lose out to any kind of attrition.
And honestly, while they can fill in for other squads, it doesn't change the fact that the other squads are much better. Forge Guard can take more damage, hit harder, and cost less. High Shields can shoot for more damage, have a much higher ARM and can soak up much more damage, and cost less (detect a theme yet?) In a very small game, 25 points or so, the OAC would be a good choice, especially in a tournament where you don't know what might be coming up next. As a fourth squad (after Forge Guard, High Shields and H&J) they'll be a good reinforcement, but as that is 21 points of squad before the OAC, you are looking at 50 point battles or bigger.