Guessing
The problem is that this kind of questions hardly ever can be answered. There simply is too much guessing.
Of course, so far, the next generation of processor is always better. That has been true the last 20 years at least and will probably be true next year as well. There is always a new generation coming.
But is it significant?
-- first of all, if you wait, you cannot benefit from todays processors now.
-- secondly, even if the new processors are faster, pulling less power and so on, does it really matter in the daily usage? For a lot of things we do daily todays, todays machines are already a bit of overkill, so what need is there for even more overkill?
-- thirdly, it might be that there are ways to upgrade the experience without waiting. One of the changes I did was upgrading to a SSD in my 2009 13" Macbook Pro. My guess (not beeing any expert) is that this makes a much larger difference in user experience than even a 10 times faster processor would do.
// Gunnar