As both a shield player and a porc lover I find myself in the odd position of both loving razors in from of other defences to draw fire and hating the fact that they drain my Felon's firepower.
I think that overall, however, razors are pretty good just as they are.
They're not invulnerable, and if you're facing a lot as a shield player the solution is to make a ton of Rogues and spam missiles at them, while keeping Felon as an insurance policy vs riots behind them.
The thing is, if (for example) razor's hitpoints was reduced, AA would become pretty vulnerable to things like Impalers.