Zaruthustran said:
Those are specific triggers, not general rules. They don't apply to Polearm Gamble's trigger.
You must be adjacent to take an OA is a pretty general rule, I think. Reach weapons explicitly do not override that rule, for instance.
It doesn't need to mention that. The OA interrupts the move, so it occurs before the move adjacent is completed.
Movement-based OAs are a general rule, they aply to all characters and all weapons - that's pretty general. OAs interrupting the triggering action are a general rule, they aply to all OAs. Being able to OA only adjacent targets is a general rule, it aplies to anyone without threatening reach - even if they have reach from a weapon, as the entry under reach in the equipment section very clearly spells out.
Polearm Gamble is a feat, and quite specifically aplies only to characters with that feat who still meet the preqs and are wielding a polearm. It can override any of the above - if it says it does.
All it does, though, is add a new trigger for your OAs: an enemy entering an adjacent square from a non-adjacent one.
That's all it does. The enemy still has to be adjacent for the OA to happen, and you still interrupt his move action - though, if he wasn't moving any farther than that adjacent square, it doesn't matter that you've interrupted it, and, if he was moving any farther, you'd get an OA even without polearm gamble, but, still, technically, you're interrupting it.
Your weapon's reach satisfies the general rule "must be able to make a melee basic attack." The attack therefore is able to occur before he enters the adjacent square/before the enemy leaves his current square.
That's a 3e way of thinking about it. In 4e, you only get an OA if the target is adjacent. Reach doesn't change that. Threatening reach changes it. So far, PCs have no way of acquiring threatening reach.
If you had polearm gamble, a reach weapon, and (just for example) a third arm with a sword, the OA from polearm gamble would only let you attack with the polearm since the sword would be out of reach
I'd think it would only let you attack with the polearm, /because the feat only works with a polearm/. Not that the rules allow for third arms or TWFing with a weapon in an extra hand, anyway, so it's a moot point. You're speculating about what the rules might be if they included such things.
If you're arguing against the OA from Polearm Gamble takes place *after* the move adjacent is completed, then you must also argue that the OA from the specific trigger "Moving Provokes" takes place *after* the move away from adjacent.
Not true, since Polearm Gamble is a specific rule, and it can thus override the more general rule on OAs.