Sasuke will surpass itachi, but ive already said that the ems is a stepping stone to greater things so, the ems apart from minor adjustments, there isnt really a difference between the two, so whilst sasuke might be stronger than itachi due to having the superior eyes it still hasnt been cleared. For example itachi's tsukuyomi is greater than sasuke's genjutsu. Sasuke is the better user of amaterasu. Susano, if you take the legendary weapons away from itachi's sasuke's is better, but equipped with them itachi's get an offence and defence boost. So even if you look at their dojutsu abilities itachi's is still slightly superior.
Then we have other aspects such as speed and reaction time which itachi is stightly better. Intelligence and strategic thinking which itachi is better. Taijutsu and and handspeed which itachi is better. Both are skilled is weapon usage and both have the advantage over the other in different departments. Example both are good at shurikenjutsu, but itachi has the greater feats, from blinding the rennigan, to his training regime. Both are good at wielding a sword but sasuke has the better feats in this and is even able to run his raiton based chakra affiliation to give his katana the extra edge
The other aspect that sasuke is better is in ninjutsu because he has shown us more ninjutsu feats outside the e/ms than itachi.
All in all sasuke still has quiet a way to go to surpass itachi, both in strength and other areas
