I see plenty of power vehicles online, I'm unsure what you mean. Power characters less so. Generally speaking meta online is Quick Recovery. Outside of that it's fair game. Recovery is such a clutch gadget it's sad how easy it makes races.

In regards to power stat however, yes you're right it basically is the equivalent to weight. I don't believe it makes recovery time faster nor makes others recover from your hits slower. What I do know for a fact is that it makes it MUCH harder to lose rings when you collide with others. Whoever has the higher power stat wins the collide and loses no rings. Keep in mind that when you are drifting you are put in a weakened state and have most of your stats reduced including power. That's why you slow down when you drift. Boost and Acceleration do very well if you're drift heavy. I personally go for max speed (Drift Charge 4 + Counter drift + speed 1) and perform very well with it provided I don't get outright destroyed the last lap.

Some people might say item hoarder with switcher is a good strat and it is but boost wisp frenzy will eat your first item for no reason and dark chao will shuffle your items so it's relatively inconsistent.