In a miniatures game, the battlespace is preset from before initiative is rolled. There is no rule for allowing the players to modify the absolute positions of things, and I think in a subtle way this confirms the boardgame mentality "This is the situation, end of story." The actions your characters may take can affect things, as specified in the rules, but the players have no input on it.
To answer your second question, the game Burning Wheel handles positioning in a very abstract manner, but I like the concept. Each character makes a statement of intent which includes a positioning manoeuvre (either close, maintain distance or withdraw). Then you all test your Agility. The highest roller gets his intent, then the second highest (unless it conflicts with the first), then the third, and so on.
So if A wants to close with B, and B wants to withdraw from A, whoever gets higher succeeds. It still doesn't answer the question of who gets caught within an area of effect, but GM adjudication is used for those cases. The important thing is not the absolute position but the relative position.
Once you have closed with an enemy, you can be within lunging distance, optimal distance or inside (the enemies guard). This gives you interesting tactical options which the D&D reach weapons don't quite match.
I use a similar approach. In a way, it's like the "the PCs are central, the world is described as relative to them" from 4E, but with regards to battlespace: Until someone wants to charge or shoot at something no one needs to know exactly how far that something is away.