Dont knock the Discovery, my wife has one and we have had a coule of issues that were not expensive to resolve, and it is to be expected in a 5yo vehicle.
When we were looking for the vehicle we looked at all the options, and the Discovery covered them all. 7 seats with the 2 boot or occasional seats folding away into a recess, therefore giving to a very large boot. also the 2 boot/occasional seats are individual were most of the other 7 seater 4x4 have bench seat (2 small seats on the bench), so its all or nothing, on the disco you can let out one of the boot/occasional, and still have a large area in the boot for all the stuff/crap we need to carry around.
I have to admit, I was sceptable about buying the discovery for the same reasins you have outlined, but they are not as bad as that.
We are into horses and the discovery is one of 3 vehicle rated to pull 3 tonnes, but its engine is 500cc less than the other 2.
the Landcruiser and the Partrol are massive compared to the discovery, and not suitalbe to all drivers, the Discovery in the other hand is narrower and shorter.
We moved away from a VW caravelle, miss some of the space, massive inside, massive boot (and I mean massive), we have the 2.4 non turbo, but you can get it isn a 1.9TDi and now a 2.5TDi, this is also worth a look.
The Discovery ticked all the boxes for us and we are well happy with our 03 Discovery TD% face lift model). and you should get a 04 for under 15k
PS, it does off road very well, were the other vehicle are more of a Urban Kerb bouncer.
Hope this helps
davrac