There's a very good reason to get rid of opaque binary blobs. If some piece of HW can write to any memory location, it having buggy firmware can corrupt internal kernel (or user space) memory silently and you have no way to review these things.
Catching bad memory writes done by HW is really hard (how _you_ would do it?). And if you don't have source, how do you fix the firmware?
Otherwise I have neutral attitude to firmware. Linux is at least on desktop too small to have much effect on manufacturers. On embedded side it may make sense to refuse binary blobs to make sure that there's open firmware... Aat least until manufacturer stops selling the HW at which point refusing the blob probably doesn't anymore act as encouragement for opening.