Obito's warping someone is very fast just look back at his fight with Minato, the first time was slow for Obito and Minato barely escaped. Changing landscapes is irrelevant when going up against Kaumi, clones didn't help Naruto out too much either.Obito needs to go tangible for attacking. Who overpowers whom if Hashirama changes the landscape and uses multiple wooden clones? Obito's intangibility lasts for about 5 minutes, Hashirama however has enough power to fight a whole day.
Obito's intangibility is 5 consecutive minutes. The reason it was successful for Konan because not only did her attack out last his intangibility she also had him trapped in one position. Hashirama hasn't shown either abilities that can trap Obito and last for 5 consecutive minutes.