I have a lazy susan, and it's okay if you don't overload it. If you spin it too fast or put too many things on, then something can fall off in the back and jam it. So it's no fun getting down on the floor with a yard stick or a coat hanger, trying to fish out the culprit! You also lose a fair amount of space with it - it's round and the cabinet is squared off, so you lose the edges/corners. It's not great for heavy things because it can get off balance. Mine is in a corner cabinet where things in the back would be totally inaccessible, and it's a decent use of that space, but it's not perfect.
It sounds to me like you might have too much stuff! It's no bargain to buy things on "special" and then waste them, or even to have all that money tied up in the pantry instead of doing some good!
Obviously the rarely-used stuff can go way in the back, but I also find it's easier to put some things in the basement on open shelves: the turkey roaster, the hot plate, the canned goods I bought on sale but don't need more than 2 of in the kitchen at any one time, the rarely-used utensils.
You may have to put "clean out" dates on your calendar - like every 2 months, pull everything out and review. Check for expiration dates and use things up or donate them to the food pantry. We also try to create interesting meals out of unusual things!
I also have a compost bin in the back yard which I use to enrich the garden or my outdoor plants. It makes me feel a lot better to recycle pretty much everything except meat, dairy and citrus in a bin with a few shovelfuls of dirt and some leaves or grass clippings.
I use some open plastic baskets from the dollar store to keep similar items organized. For example, all the rice and pilaf and lentils go in one, the pasta and noodles go in another, the various kinds of tea my husband stocks up on go in another, and things like bread crumbs and panko go in another. Soups and canned veggies like beans for tacos are together, spaghetti sauce and similar items are together. You can combine them in few baskets if you have few items.
In one of my cabinets, I have a slide out bin on rollers from Rubbermaid. A large bin on the bottom goes on runners that are screwed into the cabinet bottom, and a smaller bin on top slides back and forth. I think it's more useful than the lazy Susan because nothing is spinning. But if your island cabinet it really deep, you may have unused space behind this item.
I also have stackable containers for leftovers - some are purchased (e.g. Rubbermaid, Tupperware) and others are recycled from sandwich meat or the deli counter. Rubbermaid makes a nice set with red lids - the lids all snap together and the containers stack and then snap into the top lid. I take a sharpie marker to everything else - I sit on the floor with everything spread out, and I match bottoms & tops. Then all in a certain size get the letter "A", all in another size get "B", and so on - makes it easy to find the "mates" and to know when it's time to recycle something because it's lid-less.
You can get slide-out drawers from all of the container and closet make-over places but the cost adds up.
Herbs and spices - difference of opinion. Most people say "1 year or more - toss" but that only helps if you date the jar with your trusty sharpie. Other people don't have a very refined palate and say, what the heck, use them up.