Apparently you will now need a passport to enter the DR.
My daughter and family travelled with just birth certificates and photo ID. No problem boarding in Toronto, but when they landed in Santo Domingo they were told that they needed a passport as of Jan 23rd. They arrived on the 20th, so were allowed in but had worries about what would happen when they left.
No problems leaving the DR, but they were reminded that they will need a passport to return.
I haven't seen anything official on this yet, but I'm sure it will come soon.