Real talk: we can speculate all we want, but in the end, tradition will probably win out. If you were to ask me right now what I think Meghan will wear, this Pronovias gown is pretty close to perfect. It's dramatic and modern, with clean lines and a touch of sex appeal. It's modest without being frumpy, and it's anything but fussy. Meghan's gown will obviously be custom designed, probably by a British designer, but my money's on it looking similar to this.
As much as a formfitting or slimmer silhouette would probably suit her personal style, the truth is that Meghan's having a big royal wedding, and with that comes certain expectations. It's likely Meghan's ceremony dress with be traditional and full-skirted with a fairly high neckline, like those that came before it. I do think she'll avoid all-over lace or embellishment, choosing to add a little at the back or in panels instead. My gut tells me we're more likely to see a chic, fairly unadorned dress than an all-out embellished showstopper. Despite her fondness for breaking the rules, I don't think she'll opt for a strapless dress because I doubt the queen would allow it, but perhaps she'll have the guts to go sleeveless or add very sheer sleeves to a gown like this.
Whatever she wears, one thing is for sure: she's going to look beautiful, and no doubt there'll be copycat gowns across the globe within days!