Would you admittedly be disappointed if we didn't make at least one quality signing? This mercato is very different from the previous two under Marrotta's reign, for the simple reason, that depth was a legit excuse. We have passed that stage, and the only way this team can take things up a notch is with a bit of quality. Ibra, Lulic and maybe even Nani if we sacrifice a player is not something I'd consider unrealistic. We should be expecting that level at the very least IMO.
I'd certainly be disappointed if we didn't improve our attacking third. I take into account the signing of Llorente also.
Nani I see as a real possibility if we are interested, he's out of favour there and has one year left.
Any of the Ibra/Higuain/Sanchez/Jovetic etc deals are always difficult, it's the most difficult transfer to make for a club in our position (money to pay a market fee and salary, but not beyond that). Those are often settle by details. As I said some time before, we need our targets to not be chased by money clubs.
Ibrahimovic seems like a possibility, but I don't see any long term thinking in signing him and Diamanti plus a Lulic type player. That looks very short term, in two years we might be trying to sign a quality forward again.