If you are going to change the whole specification you should really just create a new coin. If you want to revive the existing one, you shouldn't make all these changes to it
No problem with reviving a coin and making some changes, it wasn't going anywhere in it's current state so it's not like it's hurting anything by doing this, what's the worst that can happen? It stays dormant like it was because no one was doing anything. At least this way it breathes new life into a dead coin.