1 second bandaging, kill cam
You do know that these have been removed from Realism, right?
My personal opinion:
REALISM:
--More realistic movement (17.1 seconds by my watch to sprint 100m is quite reasonable given combat load and the fact that you're not going completely all-out in order to be combat-ready upon finishing your sprint).
--More realistic health/bandaging.
CLASSIC:
--More realistic weapons, weapon loadouts, and configurations (with exception of SL loadout)
--More realistic sway and weapon handling
--More realistic pacing of combat
------overall, a more realistic feel and better immersion.
On the run-and-gun note, it's unquestionable at least to me that Realism Mode permits more running-and-gunning. It's not absent in Classic Mode by any means--it's just far less effective.
--Realism Mode's faster movement speed means respawning is less of a penalty, incentivising high-risk play.
--Realism Mode's snap-to iron sights increases the "effective range" of run-and-gun.
(Example: Stationary enemy spotted 30m away, aiming at you while you are sprinting.
In Realism Mode, one hits iron sights straight from the sprint, snaps the weapon to one's shoulder, and hoses down the target. In Classic Mode, one has the choice between stopping and using iron sights, requiring a second of fumbling with the weapon during which you will most likely be shot, and slowing down to a jog and using hipfire, which will also most likely result in getting shot when your hipfired shot/spray misses. Diving behind cover instead is thus is greatly incentivized in Classic.)
--Snap-to iron sights also allows an attacking soldier moving around indoors to closely match the reaction time of a stationary soldier camping a doorway. The defending soldier's advantage from already being in iron sights while the attacking soldier has his weapon at the hip matters little.