Well u say all high levels, yet training one since dratini lvl 15-20 will not be an east task...and i bet lots of people whill go whit the original Ash team, bulba/pika/char etc.
For me whit venusar(since it's fast when riding) and fearow, ill be happy, also the pokes streng will be determined by how u use them, casting solar beam/bullet seed (just and example) when the enemy is in front of ur poke is ok, it will be bad if just spammed and the enemy is on a diagonal place.
And also the elemt should be the correct, u could try to kill a kabuto whit a earth poke(since its rock type) and u will get owned :twisted: