FYI:
Finally I have found the permanent solution against "Waiting for Wi-Fi" Google Play Store download issue. I have had this issue and I tried everything before, but the real permanent (long-term) solution is the clean install only:
0. Install proper ADB, Fastboot, Device drivers and latest Miflash tool on your PC
1. Install latest china dev fastboot ROM via fastboot mode with MiFlash clean all flashing option
2. Install latest TWRP recovery via fastboot mode using ADB commands
3. Reboot to TWRP recovery using ADB commands
4. Wipe: Dalvik/ART Cache, Data, Cache, Internal storage
5. Reboot to Recovery
6. Copy XIAOMI.EU ROM.zip to internal storage and install the ROM (copying from PC to Phone works in TWRP recovery mode as well)
7. Reboot to system
Missing widget and Google play store download issue will be gone.
Result & proof (my own screen recorder):
https://drive.google.com/file/d/0Bx5Fv74n-TBpT1NhZ3ZaVFlsYkU/view
As you can see no more issue with the latest ominous Google Play Sore app update (version 7.6.08.N-all [0] [PR] 149245622)
Tested on Mi5