Correct, anything that helps cool the voice coil helps the situation. I was mostly refering to the fact that it is the wire heating that accounts for most of the compression.

Vents help a lot esspecially when high power is an issue. But as Duke points out, heat in a home system (using pro speakers) is not really an issue. Few people realize however, how much difference there is in the effect of heating between a smaller wide band driver (like the typical 6 1/2 inch woofer) and a large band limited pro driver. Under normal conditions heating of the pro driver is not an issue,but it is a big issue in the small driver even at normal listening levels.

There is a very good paper on driver heating in the JAES some months back. If I find it, I'll let you know.