I don't see any problem with the saw blade on the lightsaber handle. A lightsaber causes clean wounds that immediatly get cauterized, a crude saw blade does terrible and painfull things. Its not a better weapon, but it will cause a lot more terror when used to threaten or torture someone.
Oh thank god someone else said it.
I mean, we're not forgetting that these inquisitors are disciples of Sith ways, right? They may not exactly be Sith themselves but they are still disciples of such ways.
That is why they have these things.