We stayed in building #2 from 1/15 thru 1/25/13 and the bathrooms have not been upgraded. They are still the same with the bathtub and shower head. Overall the rooms are still nice though, and we have a blast as always.
We haven't heard of renovations but years ago we were given a "courtesy late checkout" room to shower in that was in block 2 (#2107), after we'd vacated our original room. This was before they had built the shower facility near Lychee.
It was a wheelchair accessible room and had no bathtub; only a shower with no/very small curb. (and a much smaller bathroom counter to provide room for wheelchair maneuvering). I suppose that might look similar to a "zero entry" shower.
Side note - people occasionally post that, except for the suites, all rooms at CN are exactly the same. Besides the mirror-image layouts, this is not, strictly speaking, true.