I used to be of that view but while standing is cool, posing is pretty awesome. If you've seen pictures of Delicate Warrior on a stand, you'll know what I mean. Completely side on sort of poses or poses that would not be in mid-air that would never be possible of holding without a stand are some of the reasons for a stand.
That said, I agree that generally a figure should have basic stability. This one lacks even that but I'm going to check following Kurdt's comment below. I think he's right b/c I remember it nagging at me when I transformed him
I think Kurdt sums it up best:
I think for those reasons it makes it a figure that is definitely worth buying.
I can't remember what I paid for MP-08 Grimlock and Thundercracker but for some reason recall it being in a similar range. Add the trailer and the beauty of the figure as a representation of Hot Rod/Rodimus (nothing has ever even come close) and I think if you shelled out for those other two, this is easily worth it and a must for any collector.
The arms also work extremely well with the matrix, He looks great either way.