Dembele is very strong and good in the more defensive side of his game, but Fulham and Spurs more recently seem to have been pushing him further and further back. He was an excellent playmaker/forward when he joined Fulham, didn't score an awful lot but was involved in everything, brilliant football brain, made things happen and that's what Spurs need.
THen Fulham moved him to a more wide striker, then more central midfielder/attacking midfielder, and at Spurs its an even deeper role to let Sig or Dempsey play ahead of him.
Chamakh looks very raw/out of form, but his movement is still good and the pass through for Gayle not long after coming on is what he's really quite good at. Given some game time, starts and form I think he can be very effective for them.