Are you sure your game is completely broken? None of the quests you tried gave you xp? Because for me the impact or the experience loss was near to zero, I don't remember any quest not giving me xp, even after patch 1.04.
Side quests naturally give way less xp than the main ones, I don't think it's a bug.
Quoting myself from this thread:
Finished the
Get junior quest. No experience for that one. Missed
500 xp Suggested level 12 / My level 16
Finished
Count Reuven's Treasure quest. No experience for that one. Missed
50 xp Suggested level 12 / My level 16
Finished
Matter of life and Death side quest. No experience for that one. Missed
100 xp Suggested level 12 / My level 16
Finished
Now or never side quest. Got experience for that one. Suggested level 14 / My level 16
Finished
The play is the thing. No experience for that one. Missed
100 xp Suggested level 11 / My level 16
Finished
A poet under preassure. No experience for that one. Missed
1000 xp Suggested level 13 / My level 17
Finished
Eye for eye quest. Got 50 xp for that one. Suggested level 12 / My level 17
Finished
Redania's most wanted. No experience for that one. Missed
100 xp Suggested level 12 / My level 17
Finished
Family blade . No experience for that one. Missed
?? xp. Suggested level 15 / My level 20
Finished
The king is dead - long live the king. No experience for that one. Missed 600 xp. Suggested lvl 16 / My level 21
Other strange occurrences:
Finished
Sword and dumpling quest (Master blacksmith). Got 18 xp for that one (2x 9xp). Suggested lvl 24 / My level 14
FInished
The Nithing quest. I got 25 xp for that one even though it was greyed out.
So that is roughly around 2500 xp since I started tracking quests. Will lose more as I progress so why should I keep playing? I would call that pretty broken in a RPG game that balances everything from Skill points, weapons, armor, quests on xp and your level.