Yeah, no. He'd still be fodder to DMS Obito. Obito is that strong because of Kamui. Hashi's DNA lets him spam it more. All Hashirama's DNA would do is let Itachi use his MS more due to the increase in physical energy, but his actual strength stays the same. Meanwhile DMS Obito (even w/o Hagoromo's power has)
-Can get up to a v4 Susanoo.
-Has Dual Kamui.
Though the latter is enough to let him rape Itachi.
He'd be incredibly strong and more capable of using MS techniques for extended periods of time and he'd certainly display feats in terms of speed superior to what he has shown.
Comparable to DMS Obito, no way. Even without Rikudou Chakra, Dual Kamui is simply too fast.
1 MS Obito? Probably.
War Arc Obito? Debatable. He'd overpower him in CQC and his has a viable offense and defense, but bypassing Kamui would be the problem.
Obito had the most hax pair of mangekyo eyes, that's why.
The big thing is Itachi gets to use his ms techniques casually. Something we got to witness with him as an edo. Also some healing and minor Mokuton techniques.