Already plenty chance of a seat on Dunblane services, it’s the E-G’s that are the problem for that. However the Cumbernauld services will likely be single unit all day due to lack of demand, resulting in the possibility of not actually getting a seat. Also, I’m pretty sure the service will take longer than currently.
Had a look at some fairly randomly chosen times on the Linlithgow - Edinburgh corridor. It's a mixed bag but looks like the majority of times are getting faster, specifically the Cumbernauld services are a good five minutes faster than the Dunblane / Alloa ones are currently.
The only area where there might be slower services is the peak Falkirk High - Linlithgow - Edinburgh services which may be slightly slower by 2/3 minutes. Unsurprisingly with an extra 2tph into Waverley the timetable reflects that all services are running at more similar speeds with the fastest services a little slower and the slowest services running faster. This should also help to smooth demand across the available services.
Linlithgow (from Dunblane current) services off peak
15 mins to Edinburgh Park
24 mins to Haymarket
29 mins to Waverley
Linlithgow (from Croy current) services off peak
17 mins to Haymarket
22 mins to Waverley
Linlithgow (from Croy current) services peak (8.06 am arrival)
16 mins to Haymarket
22 mins to Waverley
Linlithgow (from Alloa current) services peak (8.45am arrival)
12 mins to Edinburgh Park
17 mins to Haymarket
26 mins to Waverley
Linlithgow (from Cumbernauld Dec 2018) services off peak
10 mins to Edinburgh Park
17 mins to Haymarket
23 mins to Waverley
Linlithgow (from Croy Dec 2018) services off peak
16 mins to Haymarket
22 mins to Waverley
Linlithgow (from Cumbernauld Dec 2018) services peak (8.46am arrival)
10 mins to Edinburgh Park
16 mins to Haymarket
23 mins to Waverley
Linlithgow (from Croy Dec 2018) services peak (8.08 am arrival)
19 mins to Haymarket
26 mins to Waverley