I agree with that. Shieldbearers are incredible tanks, well worth their resources and food cost, especially with Bearmen, Gnoll or Trolls healers to keep them going, Bearmen and Ogres are also a dangerous heavy infantry, heck Ogre Magi can serve as one with their stats, while buffing you with Roar at the very least, and Hex around if you're good enough at micro, that you can combine with things like Bloodlust, Inner Fire, Amari's aura, Grofzag's roar, Okri's armor buff, Grella AoEs and Big Bad Voodoo... Results are very much deadly (Can talk about the Brute yet because I never picked that choice so far, but what they look like in Chapter 12 tell me they do the job too).
And it doesn't stop there. Golem are a perfectly honest 4 food unit with air attack, Mechas mow down their opposition whatever form is being used, Bloodhound do the job too, and if you want numbers, Trolls and Gnolls can give them to you while supplying 2 food units able to compare with Human ones, with orc units providing a middle ground between these mass number troops and the elites, and again, the casters... you literaly have a caster for all situations long before the campaign ends, what's more to say here?
The only units I don't use too much are Centaurs, but mainly because I do tend to prefer other ones of the list, and a personal opinion that they are at their best with Spiritcaller around, and these ladies are a bit too micro-intensive and Centaur-focused casters for me, but I was still able to see their potential during Map 8 where I sticked with Centaurs for Flammedus' group (personal decision), and it is a potentially potent combination when you can revive your assault force very easily and win by attrition.