I use this junction a lot, since I live in Barnet just to the south. This means I usually come to the junction by way of the A1081, of which you complain; it leads into High Barnet town centre.
I think you're being harsh, here. This junction is my main gateway out of London to the country beyond, as it allows me fast access to the A1 and, via the M25, the rest of the motorway network. Without the A1081 link, a large chunk of north London suburbia would be denied easy access to the motorway system. I, and thousands of others, would have to drive through Totteridge or Arkley, on local roads, to reach the A1 at Edgware. There is no need for the A1(M) to continue beyond the M25; south of this point the A1 is a normal, if very busy, urban arterial road, with many access points and roundabouts. And so it should be.
This roundabout (junction 23, as I know it) may be large and busy and have more traffic lights than is ideal, but it is hardly a nightmare.