http://imgur.com/a/IIvBB
Update:
When you pick up loot, the server just respawns over time so much waste in a (1 x 1 km?) area, that the good loot has no chance to
respawn. But if you pick up all the waste, bring it outside this zone, new loot is spawning, even in buildings where is no loot on a fresh server. So I cleared out Khelm, put the waste in front of this house, and was going to loot the good stuff. Ammo, beans, fruits, soda, weapons and
clothing. This was an experiment on Experimental BranchV 048.124674 Server "188.138.40.105:2326"; DayZ DE 0-7 (Experimental/Testing). This server is not restarting all 4 hours right now.
What I did you can see in this imgur album: http://imgur.com/a/uCM3k
tl;dr
Is the loot respawn broken? Yes and no. Server respawns, but waste will not cleared till now. So good items has no chance to spawn anymore.