Li Shenron
Legend
Do creatures with a reach of say, 10 feet, gain an AoO when you travel from 10 feet out to 5 feet out and vice versa?
What if the enemy has multiple different reach attacks? (Say one attack 10 ft reach and another a 5 ft reach?) Is the reach of the enemy equal to the highest reach attack? Is he able to OA with only a specific reach attack in each situation?
IMHO you have to keep in my the original reason for having Opportunity Attacks in the game in the first place. That reason was to punish a character who tried to:
- run away from melee
- rush past an enemy's defensive line
Older editions of D&D had simpler rules that gave your opponent a free attack at you, if you tried those ideas. Opportunity Attacks are just the evolution of such rules.
3e and 4e brought in a lot of BS'ing about attacks of opportunity, as combat became highly tactical and lots of players were just interested in exploiting rules bit, and game designers jumped into the mess because it gave them lots of design space for special abilities etc.
But if you go back to the roots of Opportunity Attacks, you see that it makes a lot of sense to stop worrying about the exact wording and possible loopholes of the RAW, and just allow one opportunity attack per enemy. It doesn't even matter exactly when you make it happen, 5ft or 10ft, it's more important why you make it happen i.e. the PC is trying one of the two moves above.