Whitebeard should have good resistance against fodder Genjutsu, Mangekyo Sharingan level of Genjutsu however would prove to be quite tricky.
@Sentinel
While it is true that One Piece characters are technically faster, I think Oda is more inconsistent with speed. In Naruto, lightning speed truly hits instantaneously, with the Sharingan having trouble to properly keeping up with A's lightning speed, with Kirin hitting Itachi instantaneously too. Meanwhile, light speed in One Piece isn't really that instantaneous. You have Kizaru firing his lasers mid range at Whitebeard, while Whitebeard is standing there having a monologue about how bright those incoming lights are, when in reality, those light's would've circled the planet 10 times. Just as pre skip characters were able to avoid those lasers. And while a much healthier Whitebeard could not react to Squardo's stab, a much sicklier Whitebeard post stab to the lungs, heart attack and his organs partially molten, with his CoO massively drained down, could still stop Kizaru in his tracks while latter was trying to travel to Luffy.
If Marco intercepting the beams means he can keep up with lightspeed, it would mean that Marco, in a second, can circle the planet like 5 times. We know it ain't happening, but rather it being a massive inconsistency.
Due to inconsistency issues I wouldn't say Whitebeard will just blitz Sharingan users.
Also, Obito doesn't have to manually activate intangibility to pass through objects. When he is in "intangible" mode, the body parts that overlap with an attack are automatically transformed into the other dimension. He has to actively switch intangibility off if he wants to lay hand on his opponent on the other hand. Hence the trick was to attack Obito only when Obito was trying to attack, since he has to be tangible. And even then he tricked them by simulating an attack. So since it is a passive ability, Obito doesn't have to react.