A clip launcher is my #1 feature request. I'd much prefer the time flow be horizontal as in Bitwig and Sonar than vertical as in Ableton.
Great care should be taken to design the relationship between the clip launcher and the product's main transport so there is maximum flexibility. Lack of flexibility here has hamstrung Ableton and poor design in this area has hampered the other DAW's. One should be able to move seamlessly between the clip launcher and the linear sequencer, never being forced into the other view when one doesn't want to be.
NOTE: There is another request for a clip launcher here. Please upvote both.