It's not really time-travel specifically - it's Johnny has a lot of tech and powers which is the same problem Dredd has (or had) with Psi-Division, Birdie, PSU etc.
Seems like it's more a case of stripping away the devices that could be used as get out of jail free cards.
E.g. time bombs become dangerous to use on yourself/very expensive/illegal, but also Johnny's mind reading powers post mortem, his jedi mind tricks, limited telepathy.
You just end up with a long list of 'why didn't he use that skill/gadget?'
Even with the scope of time bomb usage it's been pushed to breaking point - that Johnny can get from one planet to another to a specific time (and back again) in Blood Moon.