Allow user to view a list of purchase lots to be utilized (in relevant order) if user were to sell coins from that specific wallet. This will allow user to predict the cost basis to be utilized for transactions and this way optimize which wallet to sell from and how much.
As more advanced feature: Allow user to see what would be tax impact of certain transaction from certain wallet
For Koinly these type of features would be step in direction towards tax optimization software (actual guiding crypto decision) rather than pure tax reporting software. If I were Koinly I would go towards this direction.