They could be innovative and have a system where you have to submit ID to get verified as 16+ as part of your battle net account. Then it allows the option within games…not just a WC3 thing could be used across the board.
This would allow them to still sell games with a T rating, but upscale to R for adults. We also have the most disposable income.
Adults really are a market Blizzard games do not really cater for.