What suggestions should I make when reviewing a poorly written paper? Since I need a break from the reviewing...

Often in my field I review papers from researchers in Asia (reviews are not double blind) which are poorly written. By poorly written, I don't mean that the prose is not pleasing to the eye, that there are problems with how the writing flows, or that there are innocuous typos or spelling mistakes. Instead, the grammar used by the authors differs seriously from normal English, and often produces significant changes in the meaning of sentences.

Usually such papers are ultimately readable, but one has to go back and re-read sentences or paragraphs several times to infer the meaning (and this is with strong knowledge of the research area!), so I generally won't reject a paper solely for this reason. However, I would feel remiss in my duties as a reviewer if I didn't instruct the authors to improve this aspect of the paper. I'd like to provide helpful advice for the authors without just giving them a laundry list of the errors. 

Typically I highlight a few places where I had significant trouble understanding what they actually meant to say, and suggest seeking a professional editor before publication. 

Are these reasonable things to suggest? 

What other suggestions can I make?
To comment on language is fair, to suggest improvements and even making corrections goes beyond what can be expected, depending on the degree of problems. There is of course a fine line between when something can be salvaged with a little editing and where things start to lose meaning. Many journals and publishers provide services (albeit often at a cost) for non-native speakers. What you can do is to try to help the author(s) if possible by providing examples and making minor corrections. But, it is not your job to be a service. You should state your opinion about the paper, clearly separating the scientific aspect (indicate if your think the science holds) and the language issue. It is particularly potent to state when the language obscures the scientific message. In the end it is the editor who should decide what must be done.