This makes me think that they are (at least tentatively) planning on doing rewards beyond month 12. Should this program extend into month 13, 14, 15, 16, 17... 34, 35, 36, +... then eventually you could end up with some pretty hefty bonuses (IE: +5% chance to named loot items) or a stable full of VIP-exclusive mounts, etc.
IF this is the plan, then the benefits for VIP would cumulate and become better and better over time. Which incentivizes folks to stay VIP each month and provides more value based on the length of time you're VIP.
Is the dev team able to share if there are any plans to continue this program past the month 12 benefits?