Its never been much of an issue for me recently. Success based systems are easy to just reroll only failed dice and whatnot but recently playing D&D found that there is no feature to reroll specific dice and factor it into the original amount. Example, a sorcerer player rolls 8d6 for a fireball and gets to reroll up to 5 dice of his choice. This takes a very large amount of time away from the game maybe a way to click the dice we want to reroll for manual rerolls in large rolls