I'm trying to make a Pixel Wipe transition. I tried using the block dissolve with a gradient layer but the result is not what I want. I really like what I managed to do with the card wipe but I don't want the blocks to flip (cause it breaks the "pixel look"). It seems to work if I do it fast enough on a small shape cause the flip is so fast that it just does not flip (it flips in 1 frame) but I'd like to do it on the entire screen and I can't find a way to stop the flips of simply speed it so fast it's not visible.
not sure exactly how you are wiping/disolivng (directional, like left or right, or something different altogether), but you might be able to use a gradient/ramp and mosaic to create a gradient to use with gradient wipe... (remember to pre-comp the gradient and move all attributes before you can use it with the gradient wipe effect).
done right, you can get the blocks to dissolve away (rather than flip) in the order that you want.
to change the pixelation, change settings in the gradient map comp. for example, to make the wipe go from left-right, hide or remove the colorama effect. changing the ramp start and end points will further change the direction. modifying the fractal noise effect will change the pixelation pattern (you can actually animate the evolution property for some interesting effects). and changing mosaic will effect the size of the pixels.