Just about done with a Beastmen campaign on hard. I had already played their mini-campaign on Hard as well. It's been a strange campaign.
I started as Malagor, which was actually kind of annoying, cause that area is so spread out, it made it hard to raze any cities for a while, and Greenskins love to stay just out of attack range. I went up the coast line then hopped over to the Border Princes area.
I recruited Kazrak pretty quickly, and he and another general went South to continue clearing out Estalia and Tilea, while Malagor went north to finish the Border Princes, who had somehow taken land way up by the Vampires. Malagor then stayed north of the mountain ranges, attacking targets of opportunity for the next 150 turns or so.
Meanwhile, Kazrak and my other dude are having a hell of a time against the southern provinces. It seemed like every Brayherd was immediately destroyed, and I never saw a city without walls and a full stack defending it. I eventually baited them out of their cities where I could ambush them, and slowly pushed north so that I was near the other vampires, and bretonnia.
By this point, the main Dwarf faction and Undead factions have died, without me ever touching them. Malagor has been fighting fighting his way through the secondary Empire kingdoms, mostly following whatever quests I had. Kazrak and company are wiping out the other undead faction, and realizing I need to go to war with the Bretonnians soon. Turns out the Empire has been fighting with them, and the Bretonnians are down to just their capital city.
I start actively pushing to reconnect all 3 of my armies, dealing with some Dwarf sub-factions at the same time, then begin crushing Empire cities all over the place. By now, the Chaos invasion is in full swing. Malagor had wiped out everything to the north/northwest, and Chaos quickly destroyed Kislev and everything else in that direction. By the time I was done with Altdorf, Archaon was south of me, clearing some Dwarves who I had never gone to war with.
I won the short campaign victory there, and the only thing I was lacking for the major campaign was a lot more city razing. I think I needed another 20 cities. The only things left at this point are a few Dwarf settlements, some Bretonnian subfactions, and a TON of Greenskins. They were #1 strength ranking for most of this campaign, in fact. That's all I'm done now, is just mopping them up, but they're regularly sending 3-4 full stacks plus Waaghs at me near Akendorf. If I didn't have lightning strike, I'd probably be hosed.
For mainline infantry, Bestigors seem like the best choice unless you're aiming for trickery, and I typically used other unit tyes for that. I used Ungor Raiders early on as well, but it just seems like they never get better. I think you have 1 buff to their damage in the entire tech tree, while a multitude of melee buffs exist. I ended up replacing almost all of them with Warhounds, Cygors, or Razor boards.
Poison Warhounds were my choice for flanking artillery or ranged heavy armies. One army had 3 of them, and the other two had 1 each. Chaos Spawn were good early on, but I think they get outclassed by the Minotaurs. Like Chaos Spawn are good as a second wave to mop up engaged enemies, while Minotaurs could be the front line themselves if I needed.
I didn't explore the Centigor path at all, unfortunately, so I'm not sure how useful they are.
Razor boars(forget the proper name), were solid, but kinda seemed similar to chaos spawn. I treated them more like cavalry and generally used them to flank with the poison warhounds. I mostly ignored the razor chariots. I always find chariots underwhelming and finicky.
Minotaurs are obviously pretty good. I often forgot how damn fast they are. Pretty sure they're able to chase down cavalry from some of the other factions. Just alternate between Great Weapons and Shields depending on what you want them to do.
The Gorebull Hero is crazy good. I would put one in every army. He's a killing machine on his own, but he also comes with a suite of great army buffs.
The Shaman heros are also useful. I had Malagor and a Shaman summoning two Cygors into every battle. The shaman that can summon a manticore was also handy. It always seemed to have morale issues, but there were definitely times a flying monster was helpful. The other spells I didn't use as often. Typically I'd cast Devolve into large clusters as often as I could. Slowly whittled them down if my troops were struggling. Lost usefulness as the game went on.
Cygors are weird. They're much more swingy than other artillery. Like dwarf cannons, you can expect each salvo to do some damage, but it's rarely going to hit or miss with every shot. The Cygor is just throwing one giant boulder though, so when it hits, it really fucks up a unit, but it can also miss and accomplish nothing. They are more forgiving on placement, since their height allows them to throw over obstructions easily. They're also much better in melee than any other artillery. They're not as killy as a Giant, but they seem to survive longer, and have less morale issues. I used summoned Cygors to blunt charges a few different times. For ranged options, they just outclass Raiders in every way, IMO.
Giants are giants. I never recruited one, but Malagor started with one that never died. Beastmen have a lot of morale bonuses that kept it in the fight longer than normal, but overall, it's just more anti-infantry in a faction that already has a ton of anti-infantry.
So overall, I'd put a Gorebull and Shaman in every army, backed up by 6 or so Bestigor units, 4 Minotaur/Chaos Spawn, 4 Cygors, and fill in the rest with flanking units.