First if all, I'd like to say that the term "trucks" is a bit confusing for people outside of the US.

When I hear the word "truck", I'm thinking of big rigs. That said, even some of those have a place in GT in my opinion.
I've been a fan of the GT-series since the beginning, and I've played countless hours on all the incarnations up to GT4. What do I like about this series? The fact that I can choose between a huge number of cars (good & bad) and take them for a virtual spin if I want to.

I also like the fact that I can take these cars out on gravel or snow (well, most of them anyway...) and (more recently) the fact that I can customise the car a bit by changing the rims (and add an ugly spoiler

). I admit, the fact the new Photomode feature was a blessing for me!!!
I, for one, welcome the addition of (more) pick-ups, SUV's and rally vehicles, and I'd like to see even more of those. Better that, than 40 diffirent Skylines...
Just to give you guys an example of a big rig that wouldn't look out of place in GT, I'm posting the pic below. It's a rig from the company "Daf", a Dutch manufacturer, that has been run in the famous Dakar-rally in the 80's. Before any of you are going to flame me on this, I have to add that this thing was faster than the official works cars from Peugeot who dominated the event in those days!
This is what Peugeot had entered! (Also an idea for GT5!

)