First of all Obito wasn't even in combat mode. He wasn't expecting an attack. Secondly Minato has shown better reflexes than Obito, as proved by their fight.
Lastly Obito's S/T warping isnt instant, unlike Minato's FTG. Whenever he warps his whole body, there's a fading effect. Can't be bothered to find the scan right but when he was retreating after stalling Naruto and Kakashi during the Sasuke retrieval arc, you could see his whole body warped yet he head remained for a few microseconds, before it disappeared too.
Really, when Obito himself states that he was cautious of Itachi? Combat mode or no combat mode, the fact that he makes a statement immediately after using Izanagi declares this speculation null and void. He was fully expecting Itachi to kill him before he revealed the truth to Sasuke.
No he hasn't. Not from any angle. Obito's FTG was superior than Minato's way back. In fact, Minato himself declared this for Obito's S/T:
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- which obviously cannot be used without reflex actions as he uses the same technique to teleport himself or his individual parts that come in contact with the attack and is an obvious proof right from the horse's mouth. In terms of S/T, there is no comparison.
Also, if it was something automatic and not dependent on reflex action, then Amaterasu would have never made contact. It was because he was unable to react to it that hit hit him square in the frontal region of his shoulder blade. The only reason Minato even won was because he struck a second earlier, NOT because his speed was faster:
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and he escaped Twice with FTG, not his reflex action or base speed. According to Konan as well, when Obito uses Kamui to completely warp himself away instead of making himself tangible, this technique is slower in comparison.
Here, Obito effortlessly reacted to Minato's attack -
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. The fact that Obito was keeping up with KCM Naruto at Base Speed and phase through every single attack proves his superiority in this manner. Heck, even BM Naruto was incapable of landing any hit on him together with two other Shinobi.
By and By, it is a solid fact that Amaterasu cannot be evaded without intel as it spawns on the objected on which the eye is focused. A pumped 'Bijuu level' chakra into his cloak to step aside when it was spawning. That is how he evaded it. Without intel, Minato is toast.