Short answer: no! The first known exception to occur in the periodic table is in period 5: niobium’s ground state electronic configuration is:
Nb: [Kr] 5s1 4d4
which is not warranted by the “usual” rules for determining electronic configuration. So, the “half-full rule” is not sufficient in periods 5 and higher.
Let’s look at Wikipedia’s list of exceptions to Madelung’s rule. In period 4, the only exceptions are Cr and Cu, which are accounted for by the “half-full rule”. (Don’t bother too much about the dispute for Ni.)
In period 5, the exceptions to Madelung’s rule are classified in three groups:
- Mo and Ag: they are the analogues of Cu and Cr
- Pd is 5s0 4d10: a different type of application of the explanation that “fully filled shells are particularly stable”, because in this case two electrons from the s shell were pulled into the d shell. Not what you usually learn.
- Nb is 5s1 4d4, and Ru is 5s1 4d7: these cannot be explained by simple rules, and one has to perform complex quantum chemistry calculations to understand these electronic configurations.
Period 6 contains further inconsistencies, because of the introduction of f orbitals into the mix.