This point makes perfect sense to me.What made OHMSS, LTK and CR special was that in those stories, things happened to Bond, instead of just him happening to the villain's plot.
Four 'personal' films in a row and that element isn't so special any more. Having a film with a straightforward mission, with no personal involvement, would make that film special again.
Don't get me wrong, getting to know Bond on a more personal level is interesting. However, at no time do I think Mr. Ian Fleming wanted to see his penned work played out into some big personal reflection journey. The novels themselves are a little about Bond and a lot about the life he currently lives in and the situation he has to deal with then and there. Bond films should be fun, big and sexy. With that said, the films have always delivered that. Now, the series has decided to zoom in on the little human details Fleming originally established for Bond.
I do agree though, four films with the same general theme is just about enough. Come 2016, it'll be time again to adapt and change the formula.
SPECTRE's box office gross will dictate that.