I'm pretty sure Wyddr's got some Commandos hiding in the bushes to keep an eye on us Orks to make sure we don't get out of hand.
What can I say, the Ordo Xenos is good at it's job.
Dog of War is right, though - combi-charging to limit the dred's exposure to grenades is a good plan. If the "unofficial" FAQ becomes official, the options of removing a dred in close combat get much, much smaller for marines (which I think is a lousy change, as it hobbles a lot of dedicated antitank units in assault, among which are Tankbustas, Fire Dragons, Demolition Veterans, and so on and so forth).
Lootas are a pain in the butt. I will continue to destroy them as quickly as possible (well, most likely), but it's very annoying to *have* to make such plans every game.
Honestly, the only ways to keep them alive is to (1) take two units (but that eats a heavy slot, as mentioned) or Battlewagon (which also eats a heavy slot). Even in those instances, some armies (Marines in particular) can wipe them out pretty fast.