random game mode where u dont get runes or masteries

I understand what you mean BUT runes are pretty standardized or set in stone for each role you play. ADCs USUALLY take 15% AS, 8.5 AD, 12MR, 9A . Mages take magic pen, scaling health, AP and MR/CDR (conditionally). Rarely do you see someone take XP quints or death timer reduction Quints. So instead of creating diversity, as you've said, they really haven't since everyone simply chooses the most viable and refrains from experimenting since it will most likely result in a loss.