Compared to most cars, the Viper - regardless of Generation - has a lower roof line all the way around. I'm 6'1 and my Gen IV was hard to see out of the windshield until I found the sweet spot for pedal placement, seat position on the rails, and amount of seat back recline.
Once I did it was much better - but still not as good as my C7 for comparison. It's just the way the car was designed. But, I didn't buy it to watch birds fly overhead so it was just something to get used to. ;-)
The gen V - for me - is only slightly better, having driven a '14 SRT just recently. It felt the same to me as far as 'roominess' goes as my Gen IV and maybe slightly better than my son's Gen II '02 GTS. However, the Gen V was a little easier to enter and exit than my Gen IV and quite a bit easier than the Gen II - for me. Door shape and seat bolster size/design are the main reasons. But I love 'em all!
The 'get used to feeling like a can ham' comment is exactly right. These cars are focused driver's cars - you are basically strapping yourself into a nice seat for one purpose - to drive. You either like it or you don't. There are definitely roomier, easier to get in/out of, better visibility sports cars out there.
But there are also worse ones too. A Viper isn't right for everyone - there some concessions (or personality flaws, depending on your view) you have to accept to live with a snake.