Turbo diesels would generally have more low down grunt, yes, but they run out of puff much earlier than petol. Overall diesel technology has moved leaps and bounds in last 10 years or so. Mind you, 1KZ is comparitively still old technology (early 90s).
All engines are designed and made for specific vehicles/ use in mind, you can have much lower reving petrol engines such as yours or relitively higher revving in diesels as well.
Top quality diesel engines don't generally do that well here in Pakistan due to diesel quality issue. Power and torque outputs from latest common rail engines are phenominal, e.g compare the top 2.0 litre diesel in BMW producing 204hp, vs Indus corrolla 2.0d producing 1/3 of that.
Diesel has always been more popular for big transport vehicals because they are generally much more frugal and engines are built to last longer. But they have their own issues as well. Commonest being winter starting in the morning in colder regions, more frequent oil changes etc. Apart from recent german models the engine rattle noise is also significant issue (for me atleast).
I have had diesel Pajero and VW Golf in the past and had several petrol cars and a 4X4. They all had their merits and de-merits. My current LC has 1FZ, and its lovely. Got 225bhp at 4600rpm and although max torque is 387NM at 3400rpm, over 350NM is available above 1100rpm, and actually 320NM at idle, so it has massive pulling power.
I have driven a Prado TZ 1999 with 1KZ and believe me after 1FZ, it does not feel at all sprightly, infact sluggish! Granted, there is the consumption issue, 1KZ auto giving 6km around town with AC and 1FZ auto managing only 4.5km/litre (both with stable driving, not pushing hard). But than I think in the long run, lesser oil, filtesr and battery changes will even it out specially now that diesel costs the same as petrol. If you plan doing lots of motorway or long journeys than 1KZ managed 8.5-9.5km/l and 1FZ managed 6-6.5km/l. But all depends on the beast (your right foot)
Overall I am currently in favour of petrol, and thats what I would advise you to stick with. Rest is obviously upto U!