Well the Orochimaru one makes sense but how come Tsunade couldn't fight Pein before he started to nuke stuff?
Remember that Tsunade was running command & control and healing for the village's forces at the time, there were people contending with 5 other Pain bodies and Konan's paper clone. And Tsunade was also trying to extract information- Tsu likely figured it was going to turn into Hokage vs Heavenly, but when he struck first, she simply didn't expect 'first strike' to be 'city buster'.
She also had a shot to shine when Naruto was being attacked by A but didn't for some reason.
It wasn't really needed, was it? And Naruto did try and keep her out of the fight.
The Valley of the End was basically powerup vs powerup and most spent the time fighting up close(again, Orochimaru is not obligated to stick around up close).
Mostly, but not entirely. He landed some shots before foxing out at all.
True only if they engage in direct taijutsu combat. However, characters like Lee prove that even within a closed area, the faster character can basically be untouchable.
Lee was not just a little faster there, but majorly faster, though.
There was a gap of 2 fulll stat points.
From my observations, I'd peg 1.5 as about the amount of speed gap that can be fought against. At that point someone may have to rely on more of a counter-puncher strategy, but they can still fight. More gap than that is where you get blitzes.
Though even then, some people have at least defended in HtH for a time with bigger speed gaps (Ino-in-Choji vs Asuma).
Actually according to the databook, Lee was faster than Sasuke to the same degree that Orochimaru is faster than Tsunade. Depending on how much stock you put into that.
It's worth noting that Lee did the whole 'rush and attack from below' thing- i.e. a move used to catch Sharingan users off-guard.
Lee was not only faster, but had much much better taijutsu skill. He had .5 speed edge, but 1.0 taijutsu edge.
Tsunade, on the flip side, has much much better taijutsu skill than Orochimaru (who's rated at a mere 3.5 to her 5).
It wouldn't surprise me if the Strength of 100 super mode was increased physical stats either.