Sutton Harbour hold the purse strings and in todays climate that will be a definate no. The 146 isn't all that economical to operate and would only be useful for sectors out of NQY. Having worked with a flying programme containing all variants of the 146 (the ones stored at EXT funnily enough), I think reliability would also be an issue. The Dash is ideal for the current flying programme event though one is 20 years old. There will be a need for newer aircraft in future but probably younger versions of the -300. The main priority with the current fleet is to get them repainted!(dont ask me when though!)
Any 146 would be payload restricted out of PLH with the current runway length. The 143 probably operate out but empty only and even then it would be pushing it. If WOW were to look at jet equipment then I think the EMB170 would be ideal again not for PLH though.