Improvements I would like to see in PES5:
Improved/more challeging keeper AI.
More skills/dribles.
Smoother gameflow (like WE8 Int.) Better animations.
Improvements of crowd (chants/singing, waves, firework etc.) + substitution players running at the sideline and coach walking back & forth at the sideline yelling, players getting briefed by coach during matches.
Fixed the morph issue where players morph trough each other, grass etc.
Fixed the sometimes wrong offside´s, throwins, goalkicks/corner decesions.
More dynamic weather. Snowpitch very missed¨.
Better longer replays with speed´o´meter, wind stats etc.
Indoor pitches.
Full licensed players, stadium, real kits + 3rd kit, updated boots.
More IRL club/national tournaments to play.
Halftime entertainment in matches, cheerleaders, mascots etc.
BETTER commentators...!
Online play (PC, and reducing the lag issue as much as possible + more matchoptions)
Bigger/new challenges in Master League.
Thats juts some of my ideas.