You can't overcap Fury with DB. Charges are banked when you hit the Fury cap afaik or they don't proc at all. Anyway, it's the same scenario as not having DB. If you're fury capped and not using Chaos Strikes is your problem. Demon Blades cannot proc in a GCD that is used by a skill.
How is it harder? Come on. Prepared requires you to position yourself in such way you don't leave the boss hitbox when using VR. Demon Blades requires you to... nothing, just autoattack. Banking happens automatically if you've enough fury to use skills. If you don't use them, you're not banking them.
So you just said it. Demon Blades makes the rotation easier and you're forced to take another skills to fill for GCD, 'cause otherwise the rotation is dull, boring and more importantly, you can't bank charges. I don't know why you're using VR with a Demons Blade rotation and no Momentum, guess it's because of the same, so much free GCDs.
You're saying I don't take a look at my fury and plan ahead of time just because I don't use Demons Blade? Come on. Let me repeat again, you can't overcap fury 'cause when you're at 100, charges are banked. And even if they didn't, if you're not using Fury consumers at 100 Fury it is YOUR trouble and it's something even a non-Demon Blades build has to face. Not using skills = DPS loss.
And yes, we will use VR anyway. Let me repeat again. I wouldn't care about DB existence if it didn't help so much Momentum. The bank system needs to go. It is not fair I've to use 3-4 Demon's Bite (= 3-4 GCD) to get to 100~ Fury from 0 and a Demon Blades build can do it in one GCD because of the bank system. I guess Blizz didn't realize the time save that gives. If you're out of fury you should wait for the same procs I have to do to generate it, lol.