[Wendigo]

On gaining regeneration & reinvigoration through other means:

This is true, although many more item slots may be required for this: To substitute for not using lifedrain, you need both reinvigoration in excess of the unit's modified encumberance rating, and you need a whackload of regeneration.

Or no items slots at all, as you can gain both externally from spells, while using your slots for duelling gear.

In SC duelling, fights are typically short and brutal, so endurance in the form of perpetual reinvigoration is a nonissue. Of course, this just underscores the idea that tanks and tank-killers, are similar, yet have different requirements. A tank, being your typical SC, requires a weapon that is flexible and useful on the a variety of targets that it may encounter. A tank-killer, an anti-SC, only needs to be able to destroy tanks.

Indeed. Getting into the fight with no fatigue certainly helps (no penalties to att, deff & chance of armour piercing hit), but once you are hacking at each other it's mostly about att vs def, and damage yielded vs protection...and there are better weapons for that than the lifedraining ones, even at lower research levels.