Once that is overcome (and this will require compromise or redefinition, or both), there is the issue of the next Ecumenical Council being summoned by the pope and the impossible attempt of mending and reconciling the theological rift.
The Church will not be united until both "lungs" profess the same faith, which means all theological issues must be resolved, prior to reunification.
Your are correct, it is premature to express such jubilation.
On the other hand, whn two people are in love, they normally end up together despite often significant odds. When two people merely share interests, the prospect for their partnership is still remote.
The renewed atmosphere in East-West relationship suggests that maybe, hopefully, the two Churches are falling in love again, not merely decide to co-operate. So it is big news.
Watch the reunion with SSPX. If it is implemented in full in this pontificate, the road to the East-West reunification will be much clearer.