other hacked or alpha or beta kernel modules can be added as well sometimes to get something to work, but for the most part, its the kernel, thats its job, make the hardware work
the switch from xf86 to x.org some distros made was supposed to be a seamless switch, it hasnt been, there are still some problems, x.org dropped some of the older video card support for example.........sometimes you have to go back and recompile X to get things to work, especially in some of the distros which patch the heck out of some things, there's alot of dirty hacks in parts of linux