Uh, what? Hit and run attacks, as they exist in PS, simply aren't realistic. Realism is not an argument that can be used in their defense.
As far as how it's player skill alone, no, it's not realistic.
As far as realism goes in a fight, it is realistic. Duels or other one against one fights are not often "I'll stand here, you stand there, and we'll wack away at each other until one of us dies, trying to block or dodge without ever backing up or moving forwards", they are backing up, moving forwards, trying to get an edge on the opponent and keep them from being able to hit you. The system in Planeshift doesn't well mirror this (no RPG system does, as far as I've the ones I've played, although Zelda games sort of have the right idea, although I haven't played them in a while), since there isn't a character "dueling" skill, or a character "battlefield fighting" skill, it's based solely on the player's skill at moving his or her character around.
The new combat system, from what I've heard, offers a sort of balance between the two: the "hit and run attacks" still work, but the defendant can hit the person as they charge at them as long as they are facing in the right direction (since it's harder for the other duelist to time both their attacks and their opponents responses), which is useful and realistic, since as you jump in to attack someone, that someone is likely to respond by trying to stab you. (this is from the descriptions I've heard of it, I haven't done much dueling recently--in fact, at all, since the new system came out, which I'll have to try out) I think the only problem is running through your opponent, which could be solved by making any players you can openly attack (enemy guild's members, opponent duelists, and the like) solid, so that the whole "run, hit, continue on through" thing is impossible (since that's really unrealistic: I mean, you run, you hit them, and before they can hit back you go through them like the twins in the matrix, except without the cool effects or the power to actually have done that as far as setting goes--maybe a later spell will let you go through things, and that would apply to them as well, but not quite yet folks

).
Of course, if all the npcs you could attack were made solid, that could cause various issues (like "How do I get to the mine if I can't pass that Ulbernaught in the way", or "why did those people like up those ulbernaughts right across the entrance to the bronze doors?"), so I don't think that's a good idea.
By the way, dodging is already built into the game mechanics, you genius. (sigh)
As far as I can tell, that's dodging like sidestepping their lunge, or jumping over their low cut, ducking their high cut, stepping back slightly (note the slightly, the moving I was talking about higher isn't "slightly") to avoid their cut towards your ribs, moving your hand out of the way when they try to cut at that, and the like. There are more kinds of dodging an attack then that (and less agile people or those who are less skilled with their use of armor would probably use those more often).