The Objective Scoring in PVE forces players to be selfish and greedy. It's worth so much to just rush an objective and get the capture or blow up the cache by yourself. And since you have to arm the cache to get in on the points, your teammates don't care and just blow you up. This does not reward coordinated, tactical teamplay. It rewards greediness and rushing.
My proposal:
Capture objectives reward everyone who was 'near' the objective, not necessarily in the building. You can display this with a similar display for capturing ("Objective In Proximity") Everyone alive should have the objective count incremented on their scorecard.
Demolition objectives should reward everyone 'near' the objective. Everyone still alive should have the objective count incremented on their scorecard.
Please consider reworking the scorecard. It wasn't good in the original Insurgency, and it's not good in Sandstorm.