No to the latter option, as it strongly encourages the old buff servers.
As to the former, /shrug .
Gating Imperial City access can promote PvP in some ways while diminishing it in others. Best example: Darkness Falls from Dark Age of Camelot. A top-tier raid dungeon that requires PvP dominance to enter. Everyone wants in, so everyone fights for access. Everyone fights for access therefore no side controls access for long. Perpetual PvP. Best counter example: no access restriction Imperial City. Everyone's inside the shiny new zone, leaving the PvP mainstay deserted. Although with the newness wearing off some PvP guilds are leaving the city to fight on the plains once more.