Whole word has it's moments. English is a Mish mash of languages that have such a variety of phonetic and grammatical rules and norms, that it can be daunting.

Also, when you're teaching English as a second language, you have to focus on teaching language and content do there is a lot to catch students up on and no time to waste, especially since many have not only had subpar education systems, many haven't been in a school for years when they were.

I taught and tried to embed grammar lessons weaved throughout the big picture, especially because I often served multiple grade levels.