English, due to its unique development history, has lost most of its inflectional forms, it used to be heavily inflected. So, in that sense its basic grammar is said to be simpler than, say, Ancient Greek or French.
Why not give an example of a grammar point that you think I am missing?
An example I often bring up to English speakers who are learning Chinese is that they have to learn that the Chinese verbal system is based on aspect
http://en.wikipedia.org/wiki/Grammatical_aspect
rather than on tense. Many native English speakers misspeak Chinese as a second language because they struggle to impose their sense of tense on a tenseless language, and meanwhile get Chinese aspect marking all wrong. That can lead to misunderstandings in either direction, as my extensive acquaintance with persons who speak both languages often shows.
http://news.ycombinator.com/item?id=963415
Suffice it to say that Chinese grammar is NOT "trivial" to anyone who digs into it deeply. No linguist would say so. Chinese grammar, being based in large part on word order and function words, rather than on inflection, is friendly to native speakers of English, and that is one of the reasons I preferred learning Chinese to learning Russian at university while I was taking courses in both. But there is plenty of grammar in Chinese, and plenty of misunderstanding of grammar among Chinese persons that impairs understanding among people who speak differing Sinitic languages.