The C++ syntax is too terse with no reason; very simple ideas which can be written down simply are forced to be put in an ugly and incomprehensible form.
Concepts (a feature to be included in the next standard), is just a hack to put some meaningful compile-time type checking on templates, BEFORE they are instantiated.
The funny things is that they go again and introduce "late_check" to allow bypassing the "BEFORE" part and coming back to the original template type-checking "AT" instantiation.
Going back and forth, several times, just means they missed the target by a few centimeters (say, to the left) and need to "overshoot" to the other direction (the right) to hit the target. The problem is that they still miss it, again! So they overshoot to the left again! And so on. Even if they eventually converge (I doubt that), C++ will be overloaded with irrelevant historical hacks that no one knows why they were designed in this weird way.
One part of the problem is the unnecessarily terse syntax, but another part is also the perceived need to support legacy code. C++ will be much better if they stopped trying to be backwards compatible (the D language tries to do this, but is not widely adopted yet). The way things are done currently, will turn C++ into a collection of ad-hoc hacks that need deep awareness of the historical reasons to understand: reasons which will not be relevant a few years later, if not already the case now.
People stick to C++ because of its pass-by-value semantics, const-correctness, compile-time generics, interoperability with C, and wide support, but they are going to abandon it to the next language with same features and better syntax and cleaner slate (with no historical burden). D turns out to be such a candidate (see a comparison).
