While I would like them as well, I doubt we'll be seeing more invocations. Pretty much all the other caster classes that have been previewed so far have simply had new ways to expend spell slots or curated spell lists, and I can't remember any new spells being released, which I think invocations would fall under.
Patrons seem like the more likely go-to option, but they're just tied to high tier magical threats, and that's a pretty wide crap shoot. I think genies are a decent contender, and I would not be surprised at all if a vampire themed patron came about, which would actually be a decent way for PCs to live out that fantasy without being overly disruptive. I hope they avoid dragon patrons, it's too low-hanging fruit for my tastes, and steps on the toes of the dragon sorcerer, who is also a charisma based caster.
What I'd really like to see though are new pact options, which could give more leeway in bending the class. I think a swarm-focused option could be cool, as a different front-line option to blade pact, and it wouldn't be too hard to thematically link to the patrons imo. I'd also like an option for dedicated summoners, it's weird to me that the class with the strongest thematic ties to dangerous, otherworldly magical entities isn't very good at calling them to their aid.