It is quite coincidental that I have found a document published by ACM SIGMM that included a few suggestions towards running future ACM Multimedia conferences, made this January by the ACM Multimedia Conference Review committee. One of the suggestions that stands out in my opinion is an increase of the acceptance ratio from 15-17% to 20%. The document quoted the following reasons (page 5, Section 4.2):

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Many ACM conferences are experiencing greater competition in paper acceptance, along with general increase in the number of researchers and submissions in many fields, including multimedia. We therefore recommend that ACM Multimedia Conference should accept more “quality” papers, raising from the current guideline of 15-17% to around 20%.

It will signal to the community that we are now adopting a more inclusive approach rather than an exclusive attitude to accepting quality works. It will help to reduce some randomness in paper acceptance among the high quality papers when the acceptance ratio is too low (at around 15%), and there will be fewer unhappy authors.

Higher acceptance, if done with good quality control, will also allow for a greater variety of good papers to be presented, and hence help the area to grow.

Most importantly, by accepting more papers, it will go towards reducing the number of good (but rejected) papers in circulation in the conference system. It will alleviate the growth in the number of paper submitted to all the related conferences, and hence reduce the overall review loads for researchers in the field. In this respect, ACM MM should take the lead.
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I fully agree not only with the recommendation to increase the acceptance ratio, but also with the reasons, especially the last one. When serving as a program chair at various conferences, I observed that at least 20% of the papers submitted to a conference have a decent level of quality. I believe that increasing the number of accepted papers — perhaps even just slightly — will lead to a dramatically reduced number of “pipelined” papers, and a lower number of resubmitted papers draining the reviewing capacity.