Well think of it this way, Minato said Obito's Kamui was better than his FTG and look what happened; smarts and skills allowed Minato to beat a S/T jutsu he claimed to be better. FTG is a jutsu, how the user uses it also counts a lot as well.
Sasuke had to close his eye for a whole chapter after using is Rinnegan eye against Madara, he had it close while Madara went to Obito's dimension and even kept it close after Madara came back. He opened it after Sakura charged Madara and almost died, he charged Madara while Naruto saved Sakura.
Sasuke can't use it that much and if his opponent have greater foot speed/reflexes then they can dodge him as A dodged Amaterasu when it ignites where Sasuke is staring. MS Sasuke's speed couldn't react to lvl 2 lightning Armor A, so anyone with speed greater than Sasuke or a S/T jutsu themselves have high chances of not falling for Sasuke's S/T. There's also the part where Sasuke have to see his target so jutsus like hidden mist, cloud ninja's shining light jutsu they used on the Juubi, wind style dust cloud would all make that harder. There's also earth jutsus that can make the land scape rise and cover the field or use of shadow clones.
For FTG, both users are sensors, have greater foot speed than Sasuke (both beat Sasuke to the War when they all left at the same time) and can use their FTG in different ways. FTG allows Minato or Tobirama to FTG whatever they chakra touches or is connected too; what if Tobirama use water jutsu to cover the field? He can then FTG wherever his water reaches or FTG what is touching his water since his water jutsu is created by his chakra. He's played a support type and only used 2 water jutsu since he was revived; he didn't even mention edo tensei until recently.
Sasuke said "Nothing I do... works.. [pants]" and this was before he sensed Naruto since Naruto's clone didn't go to the core dimension to afterwards
You must be registered for see links
. Sasuke said his S/T jutsu is instant, that means it has no dimension of its own just like FTG doesn't; you go from A to B while Obito goes A to B to C after he warps from 1 place to another. A being where he was to B being his dimension to C being where he wanted to go.
Minato can't warp to Naruto since their chakra were merged with Naruto (yang Kurama) and Minato (Yin Kurama) and now Naruto is getting his chakra from Yin Kurama. Kurama can make his chakra into his Jinchuuriki's chakra, this is what Yang Kurama did and is why Shi, a sensor, said the kyuubi's chakra...No, Naruto's chakra. Also why Sasuke, Oro and co all sensed Naruto's chakra which Oro said instead of the 9 tails.
Like how Obito was able to warp thru Kaguya's, I think Minato could have done the same but in Obito's case, when he Kamui, he goes to the other dimension which Minato would be waiting so in Obito case, he could FTG to him as he Kamui out and go with him. Since Kamui differ from Kaguya's S/T jutsu.
Because they needed to get Sasuke back to Naruto who was buying time, Naruto and Sasuke are both needed to beat Kaguya and they weren't going to have Naruto solo fight a god that much long in case he gets killed. You want Sasuke to fight any FTG user who are not only faster in foot speed but are sensors and have instant S/T jutsus themselves? That would be one of Sasuke's worst match since FTG have more use than just moving around and can be used along with their other jutsus.
FTG allows them to go where their chakra is or is connected to; Tobirama alone can cover the field in water and FTG anywhere his water jutsu is since it's made from his chakra just like their mark is made from their chakra. Being on the Water will let Tobirama FTG Sasuke to him just like how Sasuke's S/T jutsu work but on a greater ranger. Tobirama have been made a supporter and only did 2 water jutsu, plus being Edo's means their stats are weaker than when they're alive.
Actually both Minato and Tobirama can beat Sasuke in a S/T and speed battle if they were solely relying on those jutsu and jutsus that augment their S/T jutsus.
Both have greater base speed/reflexes, are sensors, have higher intellect and analyzing skills.
You know your examples suck since those are Edo Tensei's which hever lower stats than when they're alive; Alive Minato>Edo Minato and Alive Tobirama>Edo Tobirama. Madara himself said Tobirama was hailed as the fastest of their time but he couldn't access his full power now; he said this after he pinned Tobirama down so go look if you don't believe me. Also I guess you're forgetting the important fact that Madara not only have knowledge of how FTG works, her have experiences fighting a FTG user (Tobirama). He had no knowledge on Sasuke's S/T jutsu at first but after he did he didn't fall for it again did he? When he got his other eye Sasuke's S/T jutsu didn't even have a chance to be used because at first Sasuke had to rest his eyes and Madara knew enough to stay out of the range when Sasuke opened his Rinnegan.
Madara praised Tobirama's alive speed, Tobirama praised Minato's Edo speed as being faster than his edo, Alive Minato would be faster than Alive Tobirama.
Alive Base Minato took on A (kage) and Bee (prefect Jin) more than once and enough for A to say he thought he would never be surpassed and enough for Bee to Tremble at the mention of Minato by Naruto in their training. Tobirama is on a higher level than Kage with Izuna, EMS Madara, and Hashirama. Sasuke's S/T jutsu was unknown and caught Madara by surprise, Madara wasn't at his full power nor foughtas seriously as he can, only had 1 eye which makes half his side a blink side.
Madara had knowledge of how FTG works and knowledge of FTG fighting style plus both FTG users were Edo Tensei which means they are weaker in stats than when they are alive; Madara when revived shown greater speed than Edo Madara. Sasuke also had to close his eye after Madara went to Kamui dimension and kept it closed even after Madara came back a chapter later and opened it after Sakura was stabbed and he charged Madara).
In combat, FTG can FTG attacks on Juubi level of power. In Skills it can beat a S/T Jutsu that is better than it itself (Minato stated Obito Kamui was better than his and see how that ended up). FTG can also be used with other jutsus; say I fill the field with water jutsu, I can FTG anywhere or anything that the water reach/touches. Minato already explain FTG works by teleporting wherever or whatever his chakra is or is connected to. Water jutsus are created by the user chakra just like the FTG marks so it would work on a much greater scale that way. Using this combo would let the user FTG anyone to them or go anywhere the user is as long as they are on or near the water which covers the battle field.
