My frustration with the show is they are just not using solid techniques with regard to their investigation. They should be having a full geological survey of the island completed. Also their digging is certainly not archeological. If you look at the scenes in the swamp you can see they make no effort to mark locations. Flags could be used or orange spray paint, to note locations. These seems like standard drilling technique and at least on of the Lagina brothers should be well versed in their use.
Having watched the show I have a couple of specific suggestions and a more general suggestion on how they out to proceed. Generally I think they should use the Mythbusters as consultants. They seem to be proceeding with very large scale operations when uncertain they will work. I think the Mythbusters could work on a smaller cheaper scale that would allow the Oak Island team to try more things.
I would like to see the team continue in the swamp but with something that allow the team so focus on a specific area rather than attempt to drain the entire swamp. I think what would work would be some sort of inflatable caisson, circular in shape. This would allow them to quickly drain a small area by focusing in tightly. It would also be able to move to another area should they find nothing.
My second idea would be to create a cofferdam around smith's cove and do a large scale drainage. Obviously this is costly but it would probably provide the most answers per investment. Barring this they need to dig a trench in the dry area between the cove and the money pit. Unearthing the pipe that leads to the money pit is going to be the purest form of evidence that will prove the pit is really and not some sort of sinkhole.
I would really like to see something more scientific happen in the future seasons of the show. I think they need to prove something solid with regard to the money pit. The coin found the this seasons last episode is pretty suspect as it could have been dropped by anyone, even a producer.