There will be no big megapixel announcement in april.
First Canon has to replace some lenses like the EF 16-35 II L, the EF 17-40 L ...
Both lenses don´t work pretty with the big megapixel prototypes.
i'd be interested in the new 16-35 !
I have the 16-35 2.8L II, it's my most heavily used lens.
I'd upgrade if they improve it, but I'd rather have a 18-28 2.8, or 17-24 2.8 that was cracking good everywhere and a little smaller and lighter.