5e isn't going to give a player who's used to the crunch of other editions/games what she wants. That's one of the joys of 5e - it's SIMPLE. That doesn't mean it has to be boring, though. You can evoke the crunch through words. Roleplay it. The point is to get away from numbers and math and into describing what happens by appealing to the senses.
Boring Way:
Player: I attack the orc. 2 attacks, plus Smite. [rolls] 10 and 23.
DM: 10 misses, 23 hits.
Player: 8, plus 12 from the smite.
DM: It's dead.
Not Boring Way:
Player: I bring my shield on guard, swinging my sword and singing a hymn to the glory of Torm, praying he sees fit to grant me the strength to Smite the foul orc. [rolls die] First attack, ah, crap, that's only a 10. Second attack is 23. I'll put the Smite on that one.
DM: Your first blow strikes the orc's shield. He appears shaken, his defenses slow and clumsy. Your second stroke strikes true, skimming around the edge of his shield to bite into his body. And behold, Torm has heard your prayer and your hymn, finding them pleasing. You feel the power of holy vengeance well up within you. Roll damage.
Player: Um, 8, plus 12 from the Smite.
DM: [having determined that was enough to kill the orc] Your sword bites into the orc's chest, driving deep. Your god's power crackles leaps from your arm, along the blade, and into its body, exploding from the hapless fool's eye sockets as its evil is consumed from within. Black blood streams from its mouth as it collapses, smoking and hissing, at your feet.
See what I mean?
You can do it for spells, too:
Boring way:
Player: I cast
Fire Bolt. [rolls] 19.
DM: Hit. Roll damage.
Player: 6.
DM: Okay. Not quite dead. Your turn, Brian.
Not Boring Way:
Player: A spark leaps from my fingertip and streaks toward the goblin as I utter the arcane incantation
Fire Bolt. [rolls] 19 to hit.
DM: Your spark explodes into a wreath of fire to envelop the goblin. Roll damage.
Player: 6.
DM: The goblin shrieks in anger and pain. The stench of burned goblin hair and brimstone assaults the Fighter's nostrils as the mystical flames disperse. This is just the opening he needs to move in and attack.
Anyway, you get the drift. It's all flavor text, but it's INTERESTING flavor text. It can be helpful to use the critical tables from
Rolemaster to get an idea, especially for describing killing blows. Another method is to write some descriptive phrases on index cards and keep them handy.