To be honest there is a lot you can still do with basic logic even if you don't have scripting, and if Schema-nyan and the rest of the Schine team touch up the existing logic system, which they have planned to do, then you would be able to do even more.
Of course, the issue with a block like this is how it will handle input and output. Here's how I forsee it working as the OP described it; an embedded circuit block (not related to the existing circuit/motherboard blocks), would work like a storage block; the difference of course would be that you can only place logic blocks, 1 per grid slot, and that you can connect logic blocks together within the circuit block as though they existed outside the block. Now as for connecting the internal logic circuit with external blocks... we can use the grid for that to. Basically, there would be 6 highlighted grid spots, 4 on each side and 2 in the upper left and lower right corners - each spot corresponds to a face of the block, and if you put an activation module, wireless module, or another circuit block adjacent to that face it will receive the signal from that block.
Of course you would still need to have an activation block outside of the circuit to trigger things, but this can be used to condense complex circuits down so that they take up a smaller area, while still maintaining some semblance of game balance by making sure you have all the things you need for the circuit block-wise. That's the main issue with complex circuits, like flipflop shift-registries - they take up lots of space, and may or may not be viable in some applications because of that.
Scripting, of course, has its merits; however, if we do see scripting I would like it to be part of a separate system, rather than simply a logic addon. Not to say it can't interface with our existing logic system, of course. I think having LUA scripts would allow us to perform more mathematical logical operations that in turn trigger signals within the existing logic framework - send signals if an item in an inventory block reaches a certain threshold, trigger warning lights when shields go critical, allow activation of a door or elevator only if the user enters the right numeric combo, etc. I already had an idea a while back about adding a second set of logic cubes that were arithmetic in nature, but having scripting blocks for that might be a better alternative.