I see what you're saying but I think in fact you are mistaken. A miracle is, almost by definition, something that is very unlikely to occur. When you do experiments as a scientist, you treat strange observations essentially the same way Hume says we should treat eyewitness testimony of miracles. If you observe something strange which is at odds with previous evidence, the simplest and best hypothesis is that your observations were flawed. This hypothesis should be disproved before one contemplates anything based on the strange observation.
That is why, for example, biologists have strict rules about discovering new species, and particle physicists have rules about declaring the discovery of a new particle. And that is just for discovery. To contradict a previously established law, the bar for evidence is set much, much higher. That is why when the OPERA experiment reported observing faster-than-light neutrinos last year, it was not accepted as sufficient proof that neutrinos *actually do* travel faster than light. First we had to test the hypothesis that their experiment was flawed. Their experiment was tested and it turns out it was flawed. Oops. These things happen and that's why science works the way it does.
Hume's treatment of supernatural miracles is essentially just an extension of the same scientific method we all rely on when it comes to making smartphones, microwaves, nuclear reactors, etc. A truly miraculous event in the conventional sense (e.g. a man being resurrected from the dead) would violate so many laws of physics and biology, one is tempted to say it would violate all of them. Therefore, the standard of evidence for such a claim should be even *higher* than, say, the claim that neutrinos travel faster than light.
Clearly the eyewitness testimony of, let's say, even one thousand illiterate people who saw Jesus resurrected, passed down from the 1st century, is not as powerful evidence as the testimony of one thousand physicists from the 21st century reporting a carefully controlled experiment, with graphs and data and photographs and calculations to back up their testimony. And yet, at the same time, the "miraculous" claim made in the latter case is far less inconsistent with previous evidence than the miraculous claim in the former case. In other words, supernatural miracles are less plausible, and the evidence in support of them is weaker, than some of the weakest scientific claims based on the weakest evidence acceptable in science.
So, actually, Hume's standard of evidence is reasonable and without it science wouldn't work. If miracles actually exist, then such cataclysmic breakdowns of the laws of physics should be easily detectable, and should easily pass Hume's standards--even more easily than the discovery of new particles like the Higgs.