Given the fact that Jens is aiming at a low cost peripheral, I'd imagine there's a good reason for the CPU and RAM on the card. My knowledge of the A500 expansion bus and the A1200 one isn't great, but it wouldn't surprise me if there had to be a CPU on there to provide some signals that the A500 usually doesn't provide. Plus I'd imagine the cost of a 68000 is tiny compared to the cost of development and small-scale manufacturing.
We should be grateful anyone's making any new hardware at all for our Amigas - even if it's not what we personally want, the fact that someone is making something is great - and there will be someone somewhere for whom that little side-car is a god-send. Remember just how expensive and rare A500 accelerators are! It may not be pretty but it's a pretty efficient way of expanding the market for his accelerator, and that can only help his Amiga future.
If I made some hardware, but was forced to make it external, I'd be pretty upset if I spent a year on it and it got branded as a "joke", to be honest.
