Having consistency with the already existing write methods is a good thing. And having both options is useful, as some prefer one over the other (and you can do more interesting logging things with a list of items to log whenyou aren't restricted by a format string).
Could you provide an example?
On the conditional log methods: +1 to not having them, I believe that theyare more complicating than useful.
+1 for not having the conditional log
