Perhaps Hashirama has his chances if everyone is as they were during their time in Akatsuki. However, there are still ways in which the Akatsuki can cause him problems. Just something else, intel is actually quite important in this matchup. I'll assume that Hashirama has a general idea regarding the unique abilities of each Akatsuki member. Now, Shin Sūsenju is his trump card but it can still be exploited by Kamui. Say Obito teleports Tendō, Itachi and himself to Hashirama on the statue's head. What then? Several Thousand Hands has now been rendered useless whilst Hashirama's large scale Mokuton variants, such as Jukai Kōtan, are useless on such a (relatively) small area and at such high altitudes. Is he outright beating this trio in CQC? No. Can he outnumber and deceive them with Moku Bunshin feints? Yes. Can Obito replicate Hashirama's Wood Release techniques with his Sharingan? As others have mentioned, yes he can.
I actually think Hashirama would be better off not using Shin Sūsenju. Insta-spawn a forest or two, camp and then send out waves of Moku Bunshins to do his dirty work. Any unsuspecting Akatsuki members can be picked off in the same way Tsunade was unexpectedly caught off guard by Madara's Kagerō/Mokuton combo (before she was saved by her Byakugō). Only Obito and possibly Tendō (with Shinra Tensei) are surviving such a sly tactic, but even that depends on how quickly they can react. You'd think that the Akatsuki members would benefit from having ~16 sets of eyes, but with a telepathic connection between his clones and himself, Shodai can constantly keep watch over preceedings - and he can do so without even having to reveal his true self. Only one member has a way around this and again, his name is Obito (disappearing into the ground/surroundings or his pocket dimension and reappearing allows him to maintain a sense of unpredictability).
Eventually, any member who hasn't been killed or crushed by Mokuton variants will succumb to fatigue. While Obito, Nagato and Kisame will give it a good go in the battle of attrition, none of them, in the end, will be able to outlast Hashirama - unless the latter two have Gakidō and Samehada (respectively) working overtime. I see Obito being the biggest threat if he has Nagato summon Gedō Mazō for him, but without the Bijū, Jinchūriki paths or the Kyūbi, he's going to find it difficult getting past Hashirama's doppelgangers (unless he makes some of his own, though this would just deplete his chakra further as he can't distinguish between the clones and the real Shodai. Note that the same is true for Hashirama, however). Your average Kage level shinobi is fodder at this level. If Shodai camps and makes use of guerrilla tactics instead of just going for the Jugular, he can probably win more often than not. That's not to say the Akatsuki can't win in certain circumstances. There are many combos which could prove fatal for Shodai. Banshō Ten'in + Kamui, Kamui + Shiji Hyōketsu etc...it really just depends on how the 1st Hokage plays his cards. Camping and Moku Bunshin spam is probably his best bet.
