Idea Or Sound?

[tectak]

Interesting you should say that, milo. I will always tell a student not to allow rhyme, in particular, to drive your poem. The poet must stay in control at all times, and if you have to alter your course for the sake of a rhyme then change the rhyme -- there's always another option.

Perhaps the only real option is to have a vocabulary large enough to draw from, so that sound never becomes a problem in the first place.

Yes to this. It is important, not vital, that the writer is in charge of the poem. Even when running on those rare but euphoric riffs when the poem seems to write itself you must never be consumed by the fire....though you may well bask in the heat.
This is not a metaphor. Control is always important... never stop flying. That small piece of advice, if you have to change course for the sake of a rhyme then change the bloody rhyme is pivotal. I would go further...if you have to change course because you cannot rhyme, then don't rhyme....but make that decision.
Best,
tectak