If I were going to attach something pommel end, the eastern training I've done would make me inclined to do something on a long bit of cord that I couldn't get caught on, like the tassels we used to use. Probably not the best idea for a SHTF sword though. I could see it getting caught on stuff all the time.
I'm not sure I would want to have a paracord loop around my wrist ever, but something to grab for if I were loosing it, doesn't sound TOO horrible to me. A lot of it would depend on how good the sword is. Most of the "tactical" swords that people buy these days are pretty poorly designed, IMO, with no flares or curves that would help lock the blade into one's grip. The wraps on the grips are usually crap as well, and move around, and they get very slippery. I'd like to see a pic of the sword in question, personally. Working on one's grip may be totally useless, especially because the type of grip you use can vary widely from style to style. That sort of comment tends to come either from someone trained in kendo, or minimally trained, in my experience. You'll notice, in the art of the Japanese sword, there's no flare pommel side, and the style of grip is very distinctive and rigid. In other styles, however, there are techniques involving letting the sword slip almost entirely out of your hand, and catching it by the pommel.
