I've never heard of this "chi factor" but its an interesting concept and I really like it.
I've always favored the notion that local conditions (particularly gravity from stellar, planetary, and nebular bodies) affected warp factors and thus travel durations. In some ways, its the only way to explain the inconsistencies, especially in the early years, of how far Trek ships manage to get given what has now been set in stone regarding "warp factors and velocities."
It could also directly create and affect such things as "shipping lanes." An idea that one might normally dismiss given the layman's presumption that, in space, the shortest distance between any two points is a straight line. But just like relativity and space curvature, what if that were not the case in subspace land, and there were regions of high and low resistance as well as currents of flow that aided a ship's travel time. What if subspace itself is notably denser near and around stellar phenomenon and star clusters due to higher gravity; more dangerous to navigate, but ships peel through it faster because there is more to grab a hold of. Whereas, in deep empty space, a ship might travel slower because, like a plane with less atmospheric pressure at higher altitudes, it just has less to rip through. It might be just like a propeller driven or jet engine plane that could never fly on the moon; No atmosphere to provide lift for the wings or to thrust through the engines.
It could even have the opposite effect for areas of subspace considered too
dense. Note the difference in airplane propellers, and that of a boat. The two mediums are different enough to require distinctions in their propellers. So imagine space and subspace being charted as to the optimal paths of interstellar travel. Just an idea.
It might also explain how a starship could actually experience anything unexpected like the "ion storm" of the TOS episode "Court Martial." Perhaps they only experience such phenomenon while or even because
they are at warp speeds. And because slowing down to travel through them at impulse, or going around them might cause an enormously ridiculous delay in their schedule, they can be evaluated on a scale of necessary risk, and judged accordingly. Otherwise, I couldn't imagine anything analogous to a sudden storm happening in the otherwise slow boring happenings of the cosmos; at least not on the timescale of a ftl vessel, that it couldn't take into account and just skirt around. Even solar winds and flares could be outrun by a starship and I would suspect that major issues like supernovae and the like would be steered far clear of from the outset. It would be akin to some sort of "subspace phenomenon" that has the effect of a storm, should you actually be manipulating subspace as a travel medium, but would not even be noticed if you were just passing through at relativistic speeds; certainly not in any storm like manner at any rate.
I do take issue with navigational deflectors being redundant at warp speeds however. From what I understand about warp travel, space itself is distorted around the vessel, stretched behind and contracted in front, producing the propulsive effect. The ship itself however, just sits within its little bubble of normal spacetime continuum.
Since warp speed isn't like hyperdrive where the ship itself is taken into another dimension to circumvent relativistic limitations, I'm not sure that vessels are so
certain to avoid direct interaction as you say. I'd have to see more information on this to form a better opinion though.
Final thought... I realize that I have probably over thought much of this, but the subject matter just got my brain rolling and I enjoyed the purging.