I'm been buying and selling boats in Michigan since I was 12 (between 12 - 18 I did this with my father). The last 4 boats I've owned have all been MasterCrafts and they have been by far the easiest boats to sell. You can move up the ladder with a series of wise MasterCraft purchases but you have to be smart about it. These are the rules I've used.....
Keep the boat as stock as possible - I've gone to great lengths to only upgrade the boat so that it looks like it came from the factory that way. People paying top dollar for these boats want a boat that looks factory. Anything less will in most cases detract from the sale price. If you add that tower there will be a good chance it won't be someone else's choice and you'll narrow your market. Do this only if you plan to keep the boat.
Clean, Clean, Clean - This is one area that people just baffle me in. They'll put their boat up for sale but not take the time to clean it before asking top dollar for it. They always end up leaving money on the table. Wet sanding and buffing to perfection won't cost much and will pay big benefits based on cost. That new rub rail if replaced with OEM type material will do the same. Same goes with the dash panel, detailing the engine, trailer and replacing the platform pad as long as they look like they came from the factory that way. All great affordable upgrades that will pay you back.
Avoid low ROI upgrades - Unless you plan on keeping the boat for a couple more years that PP is not going to bring you anymore money, at least not the kind that you'll put into it. Same with the tower. Let's face it each of those upgrades will end up costing 1/10 of the value of the boat a piece (if not more). It might help you sell it faster..... maybe. Do it only if you're doing it for yourself or plan to take it out before the sale.
Having you're perfect boat doesn't necessarily mean having a new or newer boat. I love the boat I have now but I sometimes miss a couple of the other boats I've owned and have on more than one occasion considered selling only to purchase one similar to one I'd previously owned. All boats have quirks and you'll need to do a lot of research before jumping into another previously owned boat (consider the vinyl issues of the early 2000 year boats as an example). It sounds like you could make this one something that would work real well for you but if you plan to sell in the next year or two be careful not to sink so much money into it that you most likely won't get it back.....
My 2 cents