Motivation goes on Zeb 99% of the time, for reasons such as we don't want to make Kanaan a juicier target and Zeb can move 8 to RR attack so he has a better shot of hitting LOS on more of your friendly targets to use motivation for its various bonuses. It isn't just in there to be used on Ezra, it can be used on 4/6 units. Doubt is great, but generally movement is the most important thing for Spectre. If you're able to get to your opponent to hit them, they really aren't going to have many focuses left to strip after round 1 and it then becomes a lot less valuable.
There are also very situational bonuses for using motivation, for instance, motivation with Zeb on Tarkin allows you to get a SC attack on their terminal sitter/challenge the terminal to deny card draw round 1. That has a potential on its own to be a game changing swing. I don't tech Motivation for that reason alone, like I said very situational, but you compact that with all of the other bonuses and it is a very solid 1 point card.
The other main reason people run Motivation is for the mirror, Doubt is useless against the mirror besides potentially one attack in the game. And that attack can be huge, absolutely, but it also requires you to give up a CC point for Tough Luck to max out the efficiency. The 1 point cards are already pretty tight for spectre, with Negation/SiN/Force Push/Deathblow, and if I am teching my CC list against hunters (who seem to do the best against SC), I'd rather have brace or stealth to help negate the effects of EOS/Heightened reflexes.
Unless you're playing against @DTDanix who EOS's Ezra's white die, I use stealth tactics to roll a dodge and he heightened reflexes the dodge
As we would say in the slack, 'gotem'.
Edited by FrogTrigger