Obito , while only using his MS , took on KCM Naruto , Guy , Bee and Kakashi and was mainly focusing his attacks on Naruto .
Naruto was hard pressured by Obito who almost warped him in 2 instances if not for Guy , Kakashi , and Bee bailing him out . He wasn't capable of damaging him on his own , all of his attacks were countered , and even admitted that Obito is too strong and couldn't get any attacks to land .
In terms of speed , Obito is able to keep up with KCM Naruto outside of his flicker as evidenced by Obito chasing him and keeping himself close . And Naruto using his KCM flicker in this fight in an attempt to evade him won't help as Obito can teleport with Kamui at Naruto .
Most of his arsenal like Chakra Arms , CORs , COFRS , FRS , and mini TBB is completely useless to Kamui phasing .
Clones are also non-factor given that :
1. Obito can dispatch them with large streams of fire that match the Juubi in size .
2. If a larger amount of clones are made , Obito can eliminate them by charging at them with Wood branches and spears , clearing them off the field in a similar way he once did to those Kirigakure ninjas .
And he is definitely not getting tagged by them as he has MS precog + intangibility in case the clones try to abuse an opening during his assault .
Not to mention that clones have slower reactions than the original which could be made worse by using them in large numbers due to chakra distribution .
With all these factors taken into consideration , MS Obito low diffs KCM Naruto as he completely counters his arsenal , and the WA trio aren't here to bail him out .
Naruto wins Low diff as Naruto brings out 15 Kage lvl clones and they jump Obito as they constantly pressure him with their yellow flash speed which is gonna create an opening for him to eat multiple FRS!