Even with latios, pikachu is not really ash strongest pokemon since his power is inconsistent (for example, in unova, league pikachu was not even strong enough to be considered part of ash A-team or even top10 and in kalos greninja was obviously stronger than pikachu). ash owned (means not released) strongest pokemon was and will always be charizard.Without that Latios feat, I doubt fans would have considered Pikachu Ash's strongest upto that point.
And though Rowlet and Rockruff aren't experienced, but pulling of a win against Olivia would mean that the assessment of their strength would be quite different after that.
To come back to the topic. a bit disappointed that again, ash only played supporting character for the totem challenge.
Like others, i hope ash will lose his trial and take a legit totem challenge for fire crystal, otherwise it would sound like the all kanto pity badges again (free pass for random good deed).
Given the turn of the events, i bet ash won't probably take the jungle totem challenge too and will only play supporting character for mallow.