Here's one thing you both keep forgetting: Waiting = DPS loss. I see that neither of you has even looked at that. This is why we try to Life Tap/Dark Pact as little as possible or while moving away from the fire, as it were. Yes, the wait time is pretty small over even a 15-minute fight, but the fact of the matter is, it's still a DPS loss. That, and .4s isn't going to mean diddly if you're getting hit with Doomfire or something similar (latency be damned).
People don't spec 2/2 Destr. Reach because their tanks suck. People spec 2/2 Destr. Reach because they're using Immolate and Shadow Bolt. Can you get 2/2 Destr. Reach in a 2/41/18 build? Yes, by sacrificing a point in Intensity, which also happens to be a DPS loss by sacrificing that point.
Also, assuming you have a paladin 100% of the time is also retarded; you can't assume every raid ever is going to have the luxury of a paladin. Case in point, 10-man raids. Does Destructive Reach suddenly become far more appealing? Yes, I'm pretty sure it does.
Now also, if you're talking 2pc T5, that's even more reason to take 2/2 Destr. Reach, because the healing caused to your pet (if I remember correctly) causes threat. (Who's the one going from topic to topic now, eh? All I've said was 2/2 Dest. Reach > 2/5 Imp. Corr.)
By the way, don't talk down to me like I don't know how to play my class; I've done enough fights where it's "stick and move," as my raid leader likes to put it, as affliction, where it's even harder than Demo with 1-2 points in Corruption. I am well aware of the mechanics of most T5 stuff, and I watch enough videos to get the idea of how T6+ content works as well. But, I will say this: Because of latency (and possibly framerate), a 1.6s Corruption with 2/2 Dest. Reach and 2/2 Intensity is better than a 1.2s Corruption with 2/2 and 1/2 Destr. Reach/Intensity (however you choose).
Oh, and one final note - Opinion != fact. So, until you come up with some facts, your argument is worthless.