Solution...
Helspar said:
The five foot move where it aggravates me the most is how someone can step easily out of combat with no ability of his/her opponent doing anything to prevent their action.
Not true... I can ready an action... my readied action is "move into the square my opponent vacates" with the trigger being "if my opponent leaves the square he is currently in." Works especially well if I'm hasted hasted... since readying an action is a partial action, I first attack you with my full-round action then with my bonus partial action (from haste) I ready "step into his square if he moves."
My opponent takes his 5' step backwards. I immediately stride 5' forwards. Obviously, if all he takes is a 5' step, he's adjacent to the square he just left (and which I just entered). He shoots his bow or casts his spell and draws an AoO.

Next round, I use a full attack then use my partial action (from haste) to ready my step again.
Alternatively, I suppose I could ready a Trip attack if he moves to keep him there.
It might be worth exploring adding a Feat similar to the Feral Ravager's "Master of his Domain" ability (or whatever it be called). Suppose it allows you to make an opposed attack roll to your opponent's Tumble check if he tries to move - anywhere - when in your threatened area. If you win, he's stuck (you don't hurt him with your attack roll, though) and can't move - not even 5' - this round.
Example step back shoot bow,drink potion, cast spell, etc.
This now becomes step back, watch me step forward, shoot bow, draw attack of opportunity. Simple.
During my next round what do I do (remember I'm hasted)? Full attack, then ready my 5' step into your square.
What ever happened to the old 2ed Combat and Tactics where stepping out of combat provoked an attack of opportunity? Moving in combat was also controlled by whoever could press the advantage. If you succeeded in your attack, but your opponent did not in theirs you could force them back, and potentially press them. The one being pressed could then be manuvered by the attacker, potentially putting them in a bad position. Really, once melle is engaged in most cases in a do or die scenario, combat is only disengaged by the death of one of the combatants.
I suppose you could use a House Rule to the effect of "if you don't move at all during your turn (including the use your 5' step to adjust during your turn), you may ready (only) a 5' step as a free action triggered (only) if your opponent takes a 5' step." Your gripe is neatly solved. If you don't move and wait for your opponent to "step back" you can "step forward." If you're busy adjusting yourself (i.e., you used your own 5' step or other motion) you cannot react quickly enough when your opponent steps away. Since it requires immobility on the part of the guy "staying with you" during his turn, it may be a fair trade-off.
--The Sigil