I do think TCX has caused quite a stir, and with MAN being leisure orientated, TCX has the right product to make it work, and, if the doubling of JFK flights is anything to go by, it does seem to be working for TCX.
I think next year will be interesting to see if LAX and BOS do well, and well enough to cause a reaction from other airlines.
Given the new partnership and focus from VS/DL, I think they are more likely to react, as VS could easily give LAX a try now they have increased their LHR-LAX offering and being a delta hub, and DL *could* try BOS on the B757 if they deem it worth a go.
In terms of TCX, the rumour is that the next new routes will go east, which in itself will be a gamble given how strong the Eastern market is from MAN, but, I wouldn't be surprised if TCX gave SFO/OAK a go, and possibly DEN for a winter market flight?