I'm not sure that that is neccessarily a dumb question. It is a very complicated one in many ways.
If you look at the complexity of many gene networks for producing a particular structure, say the development of the wing for arguments sake, the different individual mutations could lead to a great array of levels of deviation from Wild Type development. With a range going from total loss of a protein and thereby a whole signalling pathway to small amino acid changes leading to slightly enhanced/ decreased binding affinities.
The more connections a gene has in a particular network and the more fundamental the position of that gene/ network in subsequent developmental stages the greater the complexity of the events downstream will be, unless of course it just kills the thing stone dead and nothing ever happens again, i.e. something that interrupts initial antero-posterior patterning has farther reaching consequences than something which disrupts the identity of your individual digits.
In fact there are some papers suggesting that the more binding partners a protein has the more likely it is to have a conserved structure and other suggesting that this is not the case and highly connected proteins are just as prone to mutation. So whether the complexity of a proteins interactions affects its conservation is an ongoing topic for discussion.
I think that the complexity of consequences arising from a specific mutation is a reasonable thing to think about, as long as people realise that the answer is going to be different for almost every gene.
[This message has been edited by Wounded King, 04-08-2004]