To be honest, most of the bad units are only terrible some of the time.
Dreadspears and corsairs are excellent chaff units for a very low cost. They're faster than Freeguild and comparable in price. Eternal guard are the best non-elite line infantry, but that comes at a premium price and their buffs require them to stand still. With the objective game being so important now and the cost of everything going up, I think eternals are probably too expensive for such a static unit.
You're forgetting wild riders, the best cavalry in the book. Small footprint, hit hard and move like lighting. They're fragile, but also super cheap. These guys are a total sleeper unit in 3rd edition.
Even the hated Fleetmaster gets some love in this edition. He's still about as much use as a wet blanket in combat, but he has the ability to take the arcane tome artefact, which makes him potentially our cheapest and toughest elf wizard. If you have limited points available, need an extra leader, and have an artefact slot free, he's the best we have. The 3+ save against shooting makes him more resilient than anything else in that points range.
Scourge runner chariots - cheap blocker, useful to fill out battalions, fast objective grabber.