thats exactly right.
Some people think that somehow adaptation stops all of a sudden right before a population becomes a new species. This doesn't make sense. There is no built in limit to how much change can occur, and EVEN IF there were, there is no reason why that built in limit couldn't be done away with by evolution. Evolution occurs on the most basic level of life, the genetic level, and the genetics determine everything including limitations. So essentially limits to how much change can occur in evolution can NOT exist in the long run since they could easily be altered by more mutations and natural selection.
The only limits that I can think of would be basic physics. Some things aren't possible for organic life. But then again, evolution always surprises. Some of the most fascinating traits have evolved in certain species to give them an advantage in living, hunting, breeding, etc.
Evolution NEVER stops, just slows down sometimes. Even humans are evolving, but we don't know what they are evolving into. Possible answers:
Humans are evolving to be immune to health problems associated with obesity.
Humans are evolving to be less physically endowed.
Various ailments both mental and physical spread through human gene pools due to technology allowing them to survive longer and breed more.
Humans, in general, are becoming inferior because their technology removes the need to have all sorts of attributes necessary to survive. Today, even the most genetically handicapped people still live long and breed.
This brings in new issues of Eugenics, which is another topic all together.