Not everyone likes to use rhyming in their writing but it can be a real test of skill to choose a rhyme that captures exactly what you are trying to communicate. It's easy to choose a rhyme that doesn't capture your meaning exactly but sounds ok. The challenge for me, is to be totally happy with every aspect of what I have written. I often impose strict rules about the number of syllables that I use in my writing (in fact, I do so every time I write). I've often heard people praise guitar players in conversation saying things like "he doesn't waste a single note". I try to apply the same approach to writing lyrics. They have to say exactly what is on my mind, often set to a strict number of syllables (I'll match the syllables of verse 1 to the syllables of verse 2 etc) and I often impose a strict rhyming scheme. Some might say that there is no need to do this and for them that works. For me, the above really sharpens your writing skills.
I think that your three words per line approach will do exactly the same!
