Sigh do people actually read the manga they are supposed to be fans of?
All Obito would gain is Kakashi's version of Kamui and his own, that creates a combination that's basically unbeatable compared to most other MS techs. IE its strong enough already.
Kamui in both eyes:
Better defense than Sasunoo you can't be hit so why worry. Sasunoo can still be broken as shown on multiple occasions. You can call Kamui the ultimate dodge not defense lol.
Better attack than Amaterasu or at least an equal match.
The only reason Obito was ever defeated in his base form was because Kakashi had his eye which allowed him to attack Obito in his own dimension. Ergo the only person that could beat Obito was Kakashi.
Even Minato only defeated a young version of Obito, one that is likely much weaker than the current base version of Obito. And again Obito couldn't attack from range (Kakashi's Kamui tech) if he had been capable of doing that Minato would have been defeated hands down. The only reason he had the opportunity to win was because Obito had to get close and personal with Minato in order to attack, opening the opportunity for Minato to place a Hiraishin tag.
Anyway, also EMS needs a transference of eyes, something Obito can't achieve because he has no sibling. So if Obito got both eyes back all he would have is a complete set of MS eyes.