Rothbury, I sympathize with your position, but honestly, anyone who paid their passes in full previously can slide over to the new structure pretty painlessly... And when you compare the prices, it's really not bad...
The One Park Pass was $12 per month. During this initial promo period, you could either opt to pay a little less in 2018 and take the 50% off parking and blackout dates ($10 per month Basic Membership), or you can opt to spend a little more in 2018 and upgrade to the $15 per month Unlimited Membership and not have to deal with those restrictions.
And I get it. If you move to Unlimited, it costs a total of $36 per year, per pass more. BUT, here's the thing—ALL of these memberships include Christmas Town now. If we subtract last year's Christmas Town Pass price from the price difference, the new Unlimited Membership is a miniscule 50¢ more per month.
Especially given the promise of more membership-exclusives (events, promos, etc) I honestly think that is a pretty fair deal.