Subject to the next re-definition, I agree.
How confident are you that at a high "easiest-defined" phenptype level - say, chihuahuas, great danes, wolves, foxes, etc - the genetics would cause you to state they are different species.
Better said, we have defined speciation events by our definitions. You say the definitions are cast in stone today. Perhaps you are correct.
Let me try one more time. Perhaps I'm using words that are too big.
Yes, we have many definitions of species.
Yes, we add new definitions at times, and I expect this to happen again as we learn more.
Problem 1: You imply that we come up with new definitions as a way to blur the lines, or confuse things, or to be able to "move the goalposts". This is incorrect.
Problem 2: You seem to imply that the definitions were added so we could then say "we've observed speciation". We observed speciation under the older definitions, as well. We've abserved speciation under all the definitions we use. This is a non-issue.
The entire reason new definitions were proposed was when the old definitions became unuseable, not because we get speciation events under that defintion, but because we found species which blurred the lines of our definition. For example, ring species play havoc with the reproductive defintion of species.
As to your phenotype-genetics question, I think we come to the root of your problem. You seem to be saying that because the various species definitions can give different results as to what is a species, the entire concept is invalid? Is that your argument? Because a reproductive defintion draws the lines in different places than a phenotype-based definition, which draws different lines than a genetic definition?
This is actually to be expected under the modern theory of evolution. Species is a somewhat arbitrary distinction, and given the gradual nature of evolution it is expected that, no matter what defintion you use, there will be some areas where the lines are blurred. Currently, the genetic definitions offer the best distinction, and classification systems are being redeveloped to accomodate that.
You are either ignorant of the facts, dishonestly representing the facts, or both. I don't see any other way to state it.