I personally have not had an issue with a white film on my skin, or have I heard any of my customers complain. All you need is the tiniest bit!
My one call out to the white film left on the skin is lack of exfoliation. Whenever the skin is not prepped correctly it is quite easy to obtain a whitish film from any moisturizer. Whenever there is a buildup of dead skin on the stratum corneum (top layer; determines skin "beauty") any bit of moisture will mix with that to create a nasty glob of just "ew!"
However, I do agree that the SPF level should be higher. I am medium toned and so I don't burn easily. Therefore and SPF of 20 is sufficient. Being that the FDA just approved the mexoryl, Lancome did their best to put the product on the market ASAP. If you think about it, SPF 20 is a pretty good median for everyone.
Look for many other products containing mexoryl to come in the near future: body products, children's products, etc...all with SPF levels of 20 and higher!