Inf should be close to perfect in 286 IMO
Introducing a jogging speed. Your run key will toggle between a walk and jog, while holding it down will sprint, and thus reduce accuracy to a near worthless state
shooting from cover will be more effective, making for a more thoughtful game
The transition between prone and standing each has a unique animation, which doesn't occur immediately. (No more "prone hopping") Diving prone is still available, though at a cost to stamina
New collision detection for prone allows for taking realistic damage at the body, legs, and head
prone will now work as it was intended from the beginning
Introducing player inertia. This prevents instant changes of direction while sprinting, as well as a necessary distance to stop from a full sprint.
Again, shooting from cover will be more effective since it will be harder to dodge. And about hardware advantage, slower directional changes will make it easier for players with substantial lag to hit their targets.
All in all I think Infiltration will be much closer to it's goal of a truly realistic game that's still a lot of fun, even for people new to it. The only things still missing then will be mission oriented strategy, and some non-weapon equipment such as binoculars or night vision