Coliban, those windows make that a beautiful space to work in, IMHO.
I love the shelving, so would definitely keep that. Perhaps thin it out a bit, particularly regarding the non-book items (take stock of what you have, and see if you can't find a better storage solution). Don't expect that's easy, but you need space for unused instrumentation, current projects (trays), and components. And it seems to be the most logical place to put it (will currently assume you don't have space for additional shelves and such, free standing or otherwise).
And because of the view with your current desk's orientation, I'd try to avoid placing shelves on it as would usually be done to preserve that wonderful view.
The drawer unit on the underside is great, and definitely keep it (great for hand tools, probes, soldering supplies, ...). Maybe add a second when you read below.
Based on your sketch, I wouldn't bother with the tilt area to keep as much flat space as possible. In fact, I'd suggest you might want to double up on the depth (think of two tables back to back). Add a monitor arm and sliding adjustable keyboard mount for your computing needs, as it frees up valuable table space. This way, you've essentially one side dedicated to computing use, and the other for electronics work. But it also allows for additional space when needed for larger projects (think overflow for a larger electronics project when needed). The tray idea mentioned previously will really help here.
Easiest way would likely be to put the new top on the existing table's metal leg frame, build a separate table, and just butt them against one another. Should be cost effective as well.
Hope this helps.