Unit Strength appears to have no correlation on unit effectiveness aside from the amount of damage they can take past their armour. That is, if I have 200 infantry and 50 mechanized infantry, it seems to be the best move to split them all into squads of 10 (Unit Strength 1) in order to get 20 Infantry units at Power 7 and 5 mechanized infantry units at Power 8, which have the exact same damage, armour, power, movement, etc as the units I could make by putting them all together (a Power 7 Infantry unit with 20 Strength and a Power 8 Mech. Infantry unit with 5 Strength), but getting 25 more attacks per turn and with the added advantage of only taking one point of Strength damage at a time.

Of course, I understand I can't get them all to engage the same enemy, etc etc, but I also CAN get some of them to flank an enemy, and more importantly, extend my battlefield presence in all directions at very high effectiveness. As I'm getting ready to run some ground war stuff for my players, I really need to know… is there any reason in the rules to ever field units with more than a single Strength point, besides stacking them deep to defend a specific chokepoint? The battlefield my players will be on has eight sides (nine if they count separately from the side I expect them to join/aid) and no real chokepoints, only strategic terrain and objectives, so being able to spread out and hit just as hard (or harder) as they could if they focused in one place will be a HUGE asset. The sides range from 250 to 2500 fighters, equipment levels from Industrial to Modern, almost all infantry (three sides have a few Mechanized Infantry units left, and the players themselves have 200 Armour and 100 Artillery in their 1000-man regiment (400/300/200/100), though most of the sides will likely target those sooner rather than later if they're deployed (that's why none of the sides already fighting planetside have them).

By RAW, you wouldn't. On the few occasions I've bothered with using the BFK rules, I've given the players preset amounts of troops to get around this very issue.

Yeah, there are a lot of RT rules that don't seem like they were playtested with a single powergamer at the table before they were released. It took until the fourth edition of the errata until they noticed that Righteous Fury with Flamers had no rules… and when I asked on this very forum about them, I got two completely opposing answers, lol. I'll doublecheck the errata (I've glanced through the BfK errata, but didn't specifically look for this issue), and if that doesn't clarify things, I'll probably assume each battlefield has a specific unit size (determined by whatever all the units on it fit into easily)… unfortunately, owing to the numbers I'm using, we'll probably end up with squads of 50, since that'll give my smallest sides 5 units, but it'll give the players 20 (not counting the 20 units they'll be allied with at minimum), and my biggest sides will have 50 units that way. But, it's a really big battlefield (roughly the size and positioning of Antarctica on Earth) with lots of sites to fight over and not all of them important… 20 units under their direct command shouldn't be too much when they're fighting at least two other sides and probably three or four at a time. Maybe I can bump my "small" forces up to 300 and make units 100 each, that'll give the players only 10 units to manage and the largest sides 25, as well as make the players' artillery more special (it's the only artillery left on the planet, and they'll only have one unit of it…)

The sides are actually involved in three different wars, and each is allied to one in each conflict. I've got three military factions fighting each other, three religious groups fighting each other (one of the religions and one of the militaries merged, which was the worse mistake they ever made - suddenly they were fighting four sides instead of two), and three different economic groups fighting each other. The Imperial Creed is strongly aligned with the Traditions (a military group that follows standard Imperial engagement protocol) and somewhat aligned with the Mercenaries (an economic group that believes that power and wealth are one and the same), etc. The Explorers need only to ensure the Creed wins their fight, so they only have to beat the other two religious groups on the planet, not all seven other sides - though some of those sides will come to their allies' defense, they aren't main goals.

If you read the FAQ (page 11), they updated the damage that each unit does. Battalions roll 4d10, Companies 3d10, smaller is 2d10 or even 1d10. Note that the GM can roll even more damage when the disparity between army sizes is larger. So those squads of troops would be rolling 1d10 damage are a lot less likely to damage the larger units.

I personally use BfK to give me costs and relative power levels, and then use my own system of resolution. If you are going to use BfK, those differences in damage are going to make tiny units a lot less likely to score kills. The smaller units are going to disolve under fire as well. This could leave you flanked by larger units that just mow through multiple squads to get around you with their Company or even Battalion size forces.

after a re-reread of the errata, I see it now. I hate those sidebars in the PDFs, for whatever reason they're nearly unreadable and I never noticed it before. I'm glad that they reduced the damage for 10 guys shooting compared to 1000 guys, at least. I'll probably run with the new RAW, thanks for pointing it out for me - I might never have noticed it, honestly