If you're going to include Cleave, might as well include Revenge. Never had trouble personally with warriors aoe threat. I find that all our 4 abilities are plenty enough to keep targets on us. The most important thing that helps i think is always running in front of others and use Charge as much as you can. That 4-5 secs that DPS takes to reach you gives you plenty of time for doing all the threat you need.
And with Revenge critting for over 9000! with decent gear, cleave hitting 3 targets with its glyph, thunderclap and shockwave doing a pretty good job... i hardly lose aggro, even against a very well geared DPS. After you charge and use Thunderclap and Shockwave, even if DPS do crazy damage early, you can continue to spam Cleave, maybe a Revenge, Shield Slam and a 2nd TC while they are stunned to get your threat high again before the stun is gone.
Seriously, my warrior has less trouble holding aoe threat than plenty of DKs, Druids or Paladins i've seen in the hundreds of heroics i've done as a DPS or healer. All the prot warriors that i've seen having trouble with aoe threat didnt even had Revenge or Cleave in their top 3 attacks on Recount.
But if you were mostly talking about raids, ignore this post. I barely raid with my warrior, so i dont know how bad or good their aoe threat is against more than 3 DPS. :lol But the few times i did raid with him, it was just as easy from what i can remember.