Tiberius by any means wasn't an evil idiot. What was during his later reign was a diffrent matter. Also the first rebellion against the Dynasty of Augustus happened during Nero, in the later half of his reign when elites had enough of his madness. Also Augustus estabilished the political system which lasted to the middle of the III century.
Tiberius was neither evil nor an idiot but the second half of his rule was marked by purges and at best an apathy when it came to him actively administering.