Seeing as Gowron destroyed the house of Mog in DS9, there was no way the events of Firstborn could have happen in the first place, IMO.
Worf and then Alexander joined the house of Martog.
Unless Martog restored the house somehow, but the episode seemed to imply the House of Mog always stood.
I agree, TNG had a few touching scenes between Alexander and Worf, but by the time of DS9, they grew so far apart, Alexander wanted to Bat'leth the hell out of Worf for a moment.
"Generations" fundamentally altered the timeline by killing the Duras sisters, long before Gowron stripped the house of Mogh of its honor and holdings, and rendering it outcast.
Oh, and it's Martok
, not Martog.