I stopped believing in toki pona when I heard somebody say that “watermelon” would be “kili telo” (fruit [of] water). It goes without saying that “kili telo” would not be understood as “watermelon” unless they had heard it in English before, or heard someone use the English-derived “kili telo”.
If you’re going to use English-language ideas to form words, then English is a prerequisite language for speaking toki pona, and toki pona becomes useless.

I think if toki pona is developed as you describe, it could be much more useful than it is today.