I can only offer anecdotal evidence from my one recent stop there to change to the boat (and back to BTS), but even during rush hour it seemed to flow relatively smoothly.
Quite frankly I'm surprised they are making such a fuss about it.
Granted, given the way the station is set up, it may have been difficult to add the new track when the extended the line, but maybe not much harder than building the two new tracks over the river.
And given how many people I see connecting to the boats .....
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