Taxonomy is as self-correcting as any other facet of science.

However, it's just a tool for the theory; not the theory of speciation itself.

There is no GUT of speciation, but there are analyses of parapatric, allopatric, and sympatric speciation that have shown genetic divergence to a new species.

Granted, there isn't enough hard data for divergence of genera... yet. i.e. Lions to pussy cats. However, it forms a good hypothesis.

Take the example of 'Ida' recently. An ankle bone was the deciding factor between lemur and monkey.

Micro vs macro is the province of mental ingrates seeking a semantic rock to huddle under. There is no micro or macro in reality. There is just linear evolution in real time.

Think of life as a tree with bacteria at the roots and a bunch of branches at the top representing life adapted to the available niches. Life evolves from the trunk – the common line. It doesn’t evolve from branch to branch. The common ancestor, the concestor, is extinct though it may have currently living relatives. To see it we have to look into the past – into the fossil record. If a potential concestor has not become extinct then we will see it living today, a creature that has retained the same form and remains in the same niche it first adapted to fit. Like saltwater crocodiles. They are related to archosaurs, cousins of dinosaurs, and have retained the same form and niche for about 200 million years. Then there are ants. They are 168 million years old and are very closely related to each other and to the cousins of their winged forebears, which was a species of wasp. Ants have a modern evolutionary path that mirrors the evolution of flowering plants. And we know what flowering plants are, don't we? They are environmental niches to be exploited by the creatures best suited to survive in them. 

Theists, with their anthropomorphic fixation, love to drone about the non evolution of people but humans are not a great example because we’re a young species and are so closely related that our genome argues that we are actually the same race. This supports a theory that we are in fact all members of the same small, extended ancestral family that alone survived through some population trauma about 100,000 years ago. Looking at evolution from the human perspective is too limiting. You have to consider fossils with us. There are more than 20 ancestral hominids we know about and we have fossil evidence of hundreds of individuals stretching back 5 million years. This includes H floresiensis, a homind that died out a mere 14,000 years ago. That means H floresiensis shared space with H sapiens. Even given the brevity of our recent evolution we still show adaptations that have been pressed upon us by our environment since that bottleneck. Skin colour, sweat gland size, eye shape, nostril size, height, body hair, body shape and muscularity all vary based on the geography of human populations.
 
We don’t need the great leaps between species that theists cling to so they won't have to conceptualise the viewable evolution that takes place in microbes like bacteria as being possible in multi-celled creatures. But its those tiny changes that count over the long term in a process that sees a species or a branch of a species under survival pressure from a new or changing environment morphing into something new, incrementally. Theists see species as a sort of fixed law but this is erroneous. All species are in a constant state of flux in response to the pressure of survival in their environment.

OK, that is valid. However, of some note, the whole idea of a species predates Darwin by a century and was introduced in a time when nobody seriously questioned the idea of “each by it's own type”. So what constituted a species was largely the idea of two populations being cross-fertile. Of course, while the idea of a species remains of some use, that use is really not a major focus of evolutionary biology today.

One important concept that is much more current is that of a cline. A cline is a group of geographically separate populations where closely spaced groups are cross fertile with each other but more distantly separate populations lose fertility with increasing distance. A great example are the seagulls of the northern hemisphere.

Basically, the gulls from Ireland can interbreed with the gulls from Eastern North America which can breed with (for brevity) Alaskan gulls>Eastern Siberian gulls>Central Russian gulls>North European gulls. Where this becomes really notable is that the gulls from Scandinavia have overlapping territory with the Irish gulls but the two populations are not cross fertile. Such a group of populations begs the question “Where does one draw the line between the two different species?”

Another important point to note is that it is not always clear that a specific species should even be classified as such. Since the beginning of molecular biology about 30 years ago and with DNA sequencing in the past 15 to 20 years, many of what was considered to be identified species have been “moved” from one place in the tree of life to another.

One example here is that it has only been about 25 years since it became generally accepted that penguins are birds. Sure, they lay eggs and have feathers. However, some biologist suggested the while birds may have originated from velociraptors, the line that led to penguins might have originated from a species that was only related to velociraptors.

What's next are we going to have micro and macro mountain formations in the theory of plate tectonics? After all we have never seen it form a big mountain.