Well yeah, it's quite alright. Nobody dares attack the Abbasids, so I can pretty much do whatever I want. It was only annoying when one time there was an attack on my territory and I couldn't contribute to the warscore at all, and my liege didn't send any troops. I had to wait until it crept up to 100% while continuously fending of Lombardy's terryfing 200-man stacks. I'm at a three-kingdom level now, very close to the point where I could create my own empire by decision. I don't actually need the protection, but the simple fact that attacking me means declaring war on the Abbasids probably keeps the Christians in Iberia from annoying me. Those Umayyads, they didn't swear fealty. And now they're all gone.
Still, I'm rooting for the Seljuks (it's ~960 so they could appear soon) to wreak some havoc, just because I don't want to see one super-dominant realm throughout the whole game. The pope doesn't even try anymore. There was one successful crusade for Jerusalem, which was immediately re-taken. Since then, they just went for Germanics and heretics.