So having taken my first pokewalk today, observations:
2/3 of the time when you catch a pokemon, the game freezes and you get nothing. Given that you need to catch like a gazillion to progress in the game due to the leveling system, this is a bit of a problem.
After this happens and you restart the game, more than half the time you then need to keep retrying ~5min to get past login errors.
1/3 of pokestops work as intended, 1/3 of the time you need to try them 5+ times before they work, 1/3 of the time they don't work at all.
The tracking system for "nearby" pokemon is useless, broken garbage.
Gyms are all going to be held forever by turbonerds who have absurdly high-level pokemon that you can never beat.
So yeah, all in all there is some room for improvement.