I like tall tanks. Looks nice. With acrylic I would not be too concerned about the construction of the tank. Corner seams should be plenty strong.
If anything, depending on the thickness of the acrylic there could be some bowing. That's why I chose 3/4" thick for my 31" tall tank.
My observations of minuses for tall tanks:
1. Difficult to clean. Hard to reach to scrub off algae. Even vacuuming a 4 ft. tall tank would be a bit of a chore.
2. More prone to tipping over. If hit by something or an earthquake happens. If you are on a step stool when cleaning the tank don't grab the tank if you fall off the stool!
3. Really can't have a stand if a sump underneath the tank which is what I prefer.
Just remember, think about how you will reach the bottom of this tank. Cleaning, removing rocks or gravel, even catching a fish.