Weak points? Well fuel filters are definitely gonna be part of your life for the foreseeable future. I really don't know why but Astro's go through fuel filters like Bobby Hill through fried pies. If I owned an Astro I'd find a source for a case of good (wix?) fuel filters at a discount. Other than that, they're very durable vehicles. That 4.3 just won't quit. Lifting them puts added stress and speeds wear to the front suspension and cv joints...but everybody knows that. (sounds like a geico commercial)
I'm a full-time law student, full-time hospital employee (I dress up a lot) but then, and just for the discount, a part-time Auto Parts store (think O...irish) employee and part of what I do is uniquely-sold-quantity-analysis-worksheets (u-sqaws) and the most common parts for Astros (from memory here, not using company time for this) are #1 fuel filters and #2 ball-joints then blower motor stuff I think. That's obviously without counting the standards like oil filters (which would fit any 4.3, etc), brake pads, etc. Although I do think brake pads are kinda low on the Astro list unlike some vehicles that mush CHEW through brake pads to hit the numbers I see.
Also, they are a GM product which means most parts fit lots of vehicles and most parts are very reasonable for that reason. The 4.3 is 3/4 of a Chevy V8 so all engine parts are cheap (crank seals, timing chains, etc). If my big Ford hadn't fallen in my lap as cheaply as it did an Astro was near the top of my van list primarily because of the AWD availability and the ease with which they can become real 4WDs and honestly, because a v8 is an EASY swap.