There are two aspects to that:
* There haven't been any sets that take place solely on Dominaria since Time Spiral block years ago. They generally want to visit unique planes, instead of going to a new continent on Dominaria like they did in the old days.
* They have greatly deemphasized the fact that Dominaria is the center of the Multiverse. They actually did plan on outright changing Ravnica to the center of the Multiverse during the Return to Ravnica block, but they dropped that, presumably because (1) it's a rather esoteric setting detail that doesn't have a clear impact on anything, and (2) it would do nothing but anger older fans. Instead, they opted to make Jace princess of Ravnica.
i ask because i wonder if killing the eldrazi titans -> shit goes down on innistrad -> multiverse is in peril is a setup for a return to dominaria where everything's going crazy