clearstream
(He, Him)
That's right, the DMG rules leave a lacuna in -3 and -4. My recommendation based on using this in play is that groups change DC-2 to DC-4, which has the beneficial side effect of expanding the success with complication range. IIRC I suggest that in my thread on this method. Possibly some groups prefer the lacuna.I like this, but just have one question: there's a hole in the table - what happens if the DC is missed by -3 or -4?
Were it me, I'd have it something like:
Nat 20 - critical - something extra-beneficial happens
DC+2 or better - success - you do it
DC+0-1 - success with complication - you do it but something happens you maybe didn't want
DC-1--2 - failure with progress - you don't do it but something happens that moves you forward (or maybe gives a chance to try again)
DC-3 or worse - failure - you don't do it
Nat 1 - fumble - something extra-bad happens.
At first glance, the risk you'll run by adding a band is increased processing burden at the table. Someone (I can't recall who) also wrote a pretty cogent argument for why your two middle bands will likely prove redundant: success with complication being tricky to consistently disambiguate from failure with progress.
EDIT I should add that a group will also need to adopt in a set of principles. This method serves it's purpose but does not give the whole picture (which should be self-evident, and on which I have written before.)