Wasn't this just one toon?
I mean, I hear the argument that the short notice argues for a more common character, but how many guilds currently getting 6/6 Ops on Tatooine do not have anyone in the guild with an r5+ Chieftain? My guild had 2 r7s and I would have taken Chieftain to r7 tomorrow if it had been necessary (just did a small bunch of r8s and I'm short Electrium Conductors for the moment or I could have done it today).
I'm more in favour of arguing for longer lead times than I am in favour of arguing for common toons to replace their mistakes (and/or toons that become required for SMs as new missions and planets are added). Mostly because I simply think we're going to be more successful arguing for the former. And, frankly, I think that Chieftain is common enough when you're talking about the guilds that are 6/6 on Tat Ops. It's not like we need 8 copies of him.
I'm not opposed to using Sidious or whomever for these types of swaps, I just don't think that's a fight we can win, so I'm not interested in spending my energy there.