I can't agree on this.
Sure it's fine when using big metal, but if you wish to run a local airline out of Jersey or Isle of Man with EMB 120's your screwed up.
But if you want to do that, you won't be paying 1 million for a set of slots. In fact, I doubt you'd even be able to reach 50k for a set. Back when this system first came in, I worked up to 70 planes in Baku. I even opened a bug report because I thought slots were so cheap. With 342 slots already owned by me, a new full set for a week was still under 3k, it was mid-90s gametime. So if you build an EMB airline in Jersey to the point you have 50 daily flights, you should still be looking at maybe 10k to schedule the next plane, basically nothing when compared to the 400k initial lease price.
Also if you want to fly into a busy airport, slots will be significantly cheaper. In MT, I currently have 1 daily flight to EDDF. To start a 2nd one, I'd only need to pay ~200k, depending on time of day, much cheaper than the 1 million+ charged to Ezzeqiel, because he already owns 189 slots.