My! All that from a short note (for me) on haiku!
Oddly striking in all of this: most of my poetry is freeverse, just not what I choose to publish. Early on though, my sonnet writing began. And, because I was emulating/idolizing great writers I most admired, and because my dearest loves it so, I began using (however imperfectly) Elizabethan and Early Modern English. Even then, I found my way to more modern English. You will see it here and there represented. Older forms of English can be more difficult because of the syllabic changes in verb conjugations. As such, modern English is rather more flexible which, of course, is why I use the more difficult form. Besides the obvious, it’s the greater challenge.