At this point there are so many common tickborne illnesses, plus many that haven't even been discovered, that I don't see having a vaccine against only lyme as being a huge game changer. I mean don't get me wrong, it would be great, but I don't think it would suddenly make it safe to go morel hunting or whatever while wearing shorts.
That said, tick bites are mostly avoidable by following the various best practices that have been established.