I absolutely agree, as I said earlier, when it's done with artistry and for a reason, half-rhyming can be great.
Though of course "Shakespeare never has six lines together without a fault" as Dr Johnson remarked. Shakespeare wrote very fast and his work is full of small errors, not to mention the fact that the original printers changed what he wrote to make the lines fit or because they didn't have the right bits of type, so not a great example.
Also since I'm at the lectern, bath/laugh is not a half-rhyme. In a half-rhyme, the final consonants - and often the initial consonants - are the same, but the vowel sound is slightly different, eg "years/yours" or "spoiled/spilled" (from Wilfred Owen).
In assonance, the vowel sound is the same - as in "shake and quail" (from Shakespeare) but the consonats don't have to be.
In a full rhyme, the vowel sound and the final consonant are the same - as in cat/mat.
"Bath/laugh" has both a different final consonant, and, in most accents, a slightly different vowel sound. In all my professional wisdom and experience, I therefore pronounce it to be...
a crap rhyme.