I like that the Rhoman Empire isn't an unstoppable juggernaut rampaging across the world, it makes to timeline a better read as things are up in the air rather than set into a constant pattern of endless victory. I like that the two empires are eternal rivals neither able to destroy the other and as a result both present a constant threat. It's a good dynamic that prevents either Rhomania or the Ottomans from getting terribly powerful.
A bit of speculation on the future I think the Ottomans will have a similar relationship with Vijayangara as they do with Rhomania, save that the dynamic is reversed with Vijayangara having the exposed western frontier constantly at risk of being conquered or ravaged by the Ottomans. In the future might there be a pattern of alliances with Rhomania and the Ottomans both trying to get alliances that would allow them to outflank the other, i.e. Ottomans+HRE vs Rhomania+Vijayangara or Ottomans+Marinids vs Rhomania+Russian successor states.
A bit of speculation on the future I think the Ottomans will have a similar relationship with Vijayangara as they do with Rhomania, save that the dynamic is reversed with Vijayangara having the exposed western frontier constantly at risk of being conquered or ravaged by the Ottomans. In the future might there be a pattern of alliances with Rhomania and the Ottomans both trying to get alliances that would allow them to outflank the other, i.e. Ottomans+HRE vs Rhomania+Vijayangara or Ottomans+Marinids vs Rhomania+Russian successor states.