I don't think Laird changed position much at MK Dons - I think he always played the RWB / right midfielder role in a 3 at the back system.
The good and bad thing with that formation, in terms of his development, is that it gave him game time and really played to his attacking strengths - but it didn't help him address his defensive shortcomings as the role was very much centred on his attacking contribution with the RCB tasked with covering a lot of Laird's right back duties.
Because he's missed a lot of time injured, another season playing to his attacking strengths as a wing back wouldn't be the worst thing in terms of him more likely impressing and getting game time. But he really does need to start addressing his defensive weaknesses - the down side being if he focuses on the weaker side of his game, at a higher level in the championship, he might end up being dropped and struggling for game time?
Maybe a good mixture of the two for this season would be stepping up to the championship but playing the attacking RWB role under Martin again, this time at Swansea, and giving him the best chance of game time at that higher level? And then looking to focus on improving his defensive game the following season?