But if your trying to run Tank in Operations then the Full Defense Build, simple reason, Threat.
That's pretty much wrong. It's been proven time and time again that the hybrid manages better ST threat than the full Def spec does when played properly. The 2 "high threat" attacks that full Defense don't really contribute as much as you're suggesting they do, mainly because they've got comparatively poor damage and longer CDs. You don't *need* the high threat modifier when you're just dealing more damage outright, more than enough to compensate for not having a high threat modifier on 5 attacks per minute.