I would think that Londonderry should be very solid coming off their nice high school season. They have added Moloney, he has not played in a couple years, who with Corey, Del Signore and Keith Simpson should provide some solid pitching. Spaulding always puts a solid product out there as does Portsmouth. I do not know much else about the seacoast teams but for the most part they always compete. As JohnF said Nashua is missing some arms but has plenty within the 3 schools they draw from to keep them in games, Derry has some pitching that should keep them in games as well. Salem has lost some key players from last years team but added a number of Timberlane and Pelham players that could contribute to the team.
IMO, the biggest thing for teams will be the adjustment back to wood after a season of metal bats both offensively and defensively. I know that kids swing with wood all the time but it will take some time to get used to it again. Legion is always intersting because you never know who you have coming back as 19yr olds, which high school kids tryout or choose AAU, and how many schools combine into one team. There are lots of high schools in NH but 20? legion teams so certain teams can take as many schools until they reach 5000 for total enrollment.