Ibrahim and Hatice's wedding in the show is the grandest, happiest, most feastful wedding of the series, with as many celebrations as can be. It's obvious why, of course: given the show has the most "foreign politics" plots at this very point, we have to have separate moments of the ambassadors and the people of power acknowledging that whole ordeal, it's the first ever royal wedding we see in the series and it's both a payoff of so many episodes of development of Ibrahim and Hatice's story, a high culmination point, and a setup of the right upcoming close matter of the Jannisary rebellion and the future, more far looming (or that's how it merely looks like) issues of Hatice and Ibrahim's relationship (Gülfem's usual prominence is set aside for a bit to make place for Nigar); each wedding in the show signifies a major change to the status quo, but namely Hatice and Ibrahim's wedding accentuates that the most, as it doesn't just have someone permanently moving to a new place/castle (Hatice here and in E94, Nigar in E44-5, Mihrimah in E99 etc.), giving birth (Mihrimah to Ayşe Hümaşah after her own wedding, but Hürrem to Selim during Hatice's wedding) or getting wounded (Ibrahim during Hürrem's wedding, mirroring E10-E11 a bit) and new twists on established dynamics (not just the wed couples but also Mahidevran and Hürrem, SS and Mustafa, Hürrem and Leo in E17; Nigar and Ibrahim in E17 and E44-5; Hürrem, Hatice and Ibrahim, Hürrem and all the others in general in E42-3; Ibrahim and Matrakci in E44-5 etc.), but it also has a timeskip, showing the older kids to literally stress that a next stage of the characters' lives is coming forth. We get to see what a wedding is like for the first time, in its fullest and most detailed to accustomize ourselves even more in this world, so this may allow for the other weddings to lean on a more individual focus of the characters of the wedding themselves and what the wedding entails for them and those around them, the celebrations dimish and even the time the wedding's given could do so too depending on the narrative point of said wedding (more time could be given to the aftermath of the wedding than the wedding itself like in Nigar and Matrakci's case), formal weddings for ulterior, political purposes and alliances increase much more (while Hatice and Ibrahim's wedding is one of the biggest exceptions in the series and it's fascinating that we begin with it) and we get to have more bittersweetness or outright tragedy if the wedding is such for the characters. The weddings aren't only happy, they can also be like a funeral and we gradually arrive at a stage where we can actually observe that, not having it simply be hinted at (like Hürrem and Hatice's respective weddings to Lala Kasim's son and Mehmet Celebi were hinted at). The grander yet more interpersonal stakes and the bigger lean inside the empire are punctuated by the weddings as well.
{All that is to also say that it's sad that Hürrem claims that she won't get the wedding Hatice gets but Mihrimah will get it instead, when precisely hers and SS's wedding is the closest to Hatice and Ibrahim's in terms of massiveness, unprecedentedness (a big shift in traditions due to a love match as well, or rather, an even bigger one as a sultan hasn't freed and married a concubine for a looong time), structure (ceremony, feasts for the people as well as for those around the sultan and a major parallel event during the wedding, in this case Ibrahim's wounding) and feel (yes, a sorrowful element is around for everyone other than the married people this time instead of the everpresent happiness in Ibrahim and Hatice's wedding that contrasts only with Mahidevran's anguish that isn't even about the wedding, but an even bigger joy is presented for Süleiman and especially Hürrem; in E42 itself, the focus is all on the double joy with the ongoing princely circumcision and the surprising wedding in the very end, while E17 has an ongoing wedding and the surprising birth, so the focus shifts more), while Mihrimah's is a genuinely sorrowful wedding, more parallel to Hatice's E94 wedding than her E17 wedding instead.}