My next $.02.
If you are already on board with doing a new island, reworking the ref area for built in ref, don't love the microwave...I would strongly recommend looking into all new cabinets. If you want to upgrade the existing cabinets be it cleaning, shelving, painting/refinishing, drawer slides,....that's a lot of work for just a small 'L' and you are still left with some tradeoffs.
I guess I just don't see 12-15 linear feet (just the 'L') of cabinetry, getting what you want in terms of conveniences, color, door style, slides, drawers, shelving, etc, as well as matching the new island....being all that much more?
If this is a forever home, are you going to regret not getting the kitchen of your dreams?