I think the comparison between English and Tagalog is not a good idea. "He is soft" and "Malambot siya" don't really have the same "punch" in these languages.
"He is soft" (it almost sounds like "he is gay") sounds so horrible even in casual English, but in Tagalog, it just sounds very informal, but won't cause a giggle or confusion unless used in times when formal speech is necessary. It's just part of the evolution of the casual version of the language. Kinda like how "Nakakagalit" is casual, but the proper form is "Nakagagalit".
This is what makes Tagalog actually interesting. The casual speech is quite different from the formal speech.
I think that Si and Siya in Tagalog is more flexible than the English "equivalents".