I'd guess that Glasgow is a bigger destination than Dunblane for most places.
Yes, some direct links are lost but then passengers from Dalgety Bay/ Aberdour/ Burntisland/ Kinghorn don't have direct daytime services to Dundee and the world seems to cope okay - it makes sense for Dundee - Edinburgh services to omit smaller stations south of Kirkcaldy (with a local service catering for journeys between Kirkcaldy and Edinburgh), just as it makes sense to speed up the Stirling - Edinburgh services with capacity at Polmont/ Linlithgow to be provided by another service.
If the Cumbernauld - Edinburgh is going to be as low as people are suggesting then the "downgrading" from a four coach 158 to a three coach 385 will still mean more seats at Polmont/ Linlithgow, since they won't have to fight against Stirling passengers.
Camelon sems to get many more services than passenger numbers "deserve", but then what's the simple alternative? The new proposal gives good connections between Gatcosh/ Cumbernauld and Stirling every half hour. Dropping the Stirling calls completely would cause problems (unless people think that Camelon passengers should be forced to double back to swap platforms at Grahamston whilst it's unfair for Linlithgow passengers to have a same platform interchange?). Going down to just hourly on the Stirling services (and Cumbernauld service?) would remove a lot of the interchange opportunities between Stirlingshire and Lanarkshire.
Cumbernauld is a large place, as
@Altnabreac says, and a growing one too - I think that some people overlook populations changes - historically "large" places aren't always so big in the twenty first century. Like the threads where people complain about "InterCity" services from Edinburgh to Inverness stopping at "small" places like Kirkcaldy, ignoring the fact that Kirkcaldy is bigger than Inverness. Plus Cumbernauld has rail links to Coatbridge etc, for through services to Falkirk etc (ignoring the A2B direct services from Monklands into Edinburgh).
