How easy is it to replace an ignition switch on a 1994 Jeep Wrangler?

You did not clarify whether you meant the switch or the lock cylinder that drives the switch. Either way, it is a complex job that requires special tools and a high degree of mechanical ability. In essence, you will have to remove the entire steering assembly if you need to replace the switch. If it is just the lock cylinder, it is considerably easier but still complex requiring removal of horn, turn sig, hazard and other assemblies. I have done this on an 89' and 93' Wrangler, a 94' shouldn't be much different. If you need details, e-mail me at: iancarah@yahoo.com...but to answer the question: It is not easy.