Yes, Viggo was a pretty wimpy Aragorn. at the time of LOTR Aragorn is about 45, so he should have been stronger and maybe a little harsher, like a young Rumsfeld...
Actually, the book-Aragorn was 80 or so, much closer to Rummy's age. Lord Aragorn was pure Numemorean stock, and lived to the ripe old age of 240.