Changes to random encounters are probably one of the things I appreciate the most in pokemon hacks, and I'm really pleased so far.
I killed off Brock on my first try with lv14
, lv16Wartortle, lv12
and lv15Mankey.
The first one was probably the most valuable asset to the team, it killed off about half of the enemy team before his HP went down low enough to switch out, and I still had Wartortle and Mankey around so I didn't even have to use any items.
Oh, and
shiny onix 
EDIT:
Both Misty and Surge gave some big trouble, but replacing
with
paid off, and having Primeape and
at level 31 for the latter one made it a lot easier, so I managed to beat both of them on my first try as well. Kind of barely made it on both, specially Misty, I had to use the only revive I had against her.
This hack is proving to be more challenging and fun just by making these harder, unlike resorting to the hellish, tedious dark mazes that the harder Touhoumon hacks all have. I like it.