The transferring aspect is variable depending on reasoning and circumstances. There might be reasons to leave as-is for a while longer and there might be reasons why you should transfer it. We probably need more information to give a more thought-out response. There certainly is no harm in leaving it for another week or two in primary though, unless you need your fermenter for another batch in which case you should check gravity (at least).
Regarding the krausen still on top. I've worked with a few ale yeasts that simply don't like to fall. In those cases, I'll either given them a hand by jostling the fermenter a little bit, a few times, to encourage the krausen to begin sinking, or I'll just rack from under the krausen. It kind of depends on my schedule and how long the beer has been sitting that way. The three strains whose krausen has lingered on top for a long time have been: Westmalle Yeast (i.e. WY3787/WLP530), Odell Yeast (i.e. WLP029 German/Kolsch), and Brewferm Blanche Ale. Once I've jostled; once I've waited; twice I've racked from underneath; and once I've collected the krausen for later use and racked.
(gentle rocking would be perfect).
