I haven't followed them closely, just checked in from time to time. One issue appears to be that if a diplomat stays at the Trump hotel in DC, that's really the diplomat's own choice and not something Trump is involved in. At the same time, however, it seems that the Trump admin hasn't proactively told people not to stay at Trump hotels (that I'm aware of) and so this could still be construed as 'accepting' value from foreign diplomats. So I'm left to conclude that President Trump must be insulated enough from the businesses, at least while he's in office, that this isn't an issue.
So these aren't in my core area of expertise, but I don't think your conclusion that "it must be fine" is warranted.
A big chunk of the issue is "who has the right to sue" over it. Every lawsuit requires an injured party to be the Plaintiff. And that injury has to be "real" in the sense that there's something that the court can do, in response to the complaint, that would address it.
The quickie three element version of "do I have a right to sue" is:
1) Injury in Fact
2) Connected to Actions by the Defendant
3) Redressable by the Court
The Emoulments thing is tricky because, even though it's clearly provided for in the Constitution itself, it affects everybody in an abstract way but no one person in a totally obvious and concrete way. Further, the United States rejects "taxpayer standing" so that taxpayers can't sue the Government for violating rights on the basis of "I pay taxes, do your job."
One way to go about this, with respect to the G-7 summit, would be another hotel owner
who would have obtained the contract absent the President directing a contract to himself (say someone who'd had the event before, like the resorts at Sea Island, Georgia), and could then claim that they were denied business by the decision to allow the president to profit. This has it's own problems. It's speculative and it would be difficult to prove that you actually were injured unless you could get testimony saying that the contract was coming your way until the President stepped in.
Some abstract harm cases have specific laws that grant people standing to sue under them, but no one has ever created one for Emoulments because no one has ever tried to run their business empire at the same time as the country before.
No one has ever made any substantive judgments about the emoulments case against Trump. There's a procedural problem that's prevented it from ever getting a real hearing. Stop giving this guy the benefit of the doubt!