I see alot of Feats that specify "Adjacent Square" to activate (Advance, Step Up, etc)
IMHO, these should all be based on threat area, either yours, the enemy's, or both.
For example, a Longspear wielder DOESN'T want to move ADJACENT to the Giant Dragon to attack, they want to be in threat range (10').
Here's my reworking of Step Up, as an example of Threat Area-neutral wording:
Step Up (Combat)
Benefit: Whenever a foe who threatens you or is threatened by you, moves away from you, you may also make a 5-foot step as an Immediate Move Action so long as either you or the foe that triggered this ability end up within each other's threat area. If you take this step, you count as if you had take a 5-foot step on your next turn.
Improved Step Up/ "Step Back"
Benefit:Whenever a foe moves towards you, placing either you or the foe within each other's threat area, you may also make a 5-foot step away from the foe as an Immediate Move action. This otherwise works like Step Up.