For a long time, people have been calling Darius, a Garen 2.0. Why not go with this idea?
This is just my opinion, feel free to hate 
Darien/ Garius: DARIUS+GAREN
Passive: Hemorrhage *unchanged/ change it to more stack but offer less strength*
Q: decimate (deal 25% less damage to minions/ neutral monsters)
Cost: 30 mana (each successive strike within 5 seconds costs 5 additional mana up to a cap of 60 mana) Apply a stack of hemorrhage
W: Strategic Strike (Decisive Strike + crippling strike)
= removes all slow affecting him and gains 35% bonus speed for a duration 1 / 2 / 3 / 4 / 5 s next attack within 5 seconds deal 100 / 110 / 120 / 130 / 140 % of attack damage as bonus physical damage + 20 / 25 / 30 / 35 / 40 % slow.
Upon reaching 3 stacks of hemorrhage, the target will be silenced for 1.5 / 1.75 / 2 / 2.25 / 2.5 s seconds.
(cannot critical strike) 10 seconds cool down at all rank
cost: 30 / 35 / 40 / 45 / 50 mana
E: Apprehend
Passive: Grant 4/8/12/16/20% bonus armor and magic resistance
Active: Pulls in all enemies with hemorrhage debuff in front of him
for each enemy champion he pulls, he gains bonus 2 / 4 / 6 / 8 / 10 % penetration for 2 / 3 / 4 / 5 / 6 seconds
cost: No cost
R: Guilotine of Judgement
After brief channeling, ... crashs down to enemy champion and deal:
120/240/360 true damage and additional magic damage per 3/2.75/2.5 enemy's health missing. Cannot perform on the same target twice within 30 seconds.
base cool down unchanged but added cdr and removed cool down refresh:
cdr per hemorrhage stacks on target = 18%/ 36%/54%/72%/90%
cost: 100/125/150 mana