I think the problem with Master 08 tournament battle is that they lack intensity and power that you expect from Champion. Just look at this --
https://www.sakugabooru.com/post/show/128865This entire full battle took place for about 1 miunte & half yet it had more intensity than main anime battle. Goodra flooded the whole stadium, Aegislash made a huge crater , Flygon's Stone Edge is probably 50 or 100 meter tall, Duraludon summon actual comets etc etc. This is the level of power that Champion's Pokemon should have shown in the Mastesr 08 Tournament. Compare to that, main anime champion barely made a scratch on Battle Field.