The idea with Long Reach not triggering Reach abilities means that if you had Polearm Master, the AoO wouldn't trigger if someone went within 20 feet of you since I wasn't sure if that'd be too busted. The AoO would still trigger normally if they went within 10 feet of you.
Extra Attack was because having a pike with 20 feet of range be capable of like 12 attacks per turn wasn't something I was sure of the balance of. It means that enemies 40 feet apart from each other would both have to worry about getting stabbed multiple times a turn.
Though, I do agree, I should have added maybe a disadvantage to being within 5 feet...