Sadly, tryn just doesn't seem viable like most AA melee champions with no real damage outside of AA, hes a little easy to kite, and gets outclassed by most other top lanes. In my opinion the Problem with tryn is though if you don't get that control and its a bit more equal, pretty much every top laner beats tryn if tryn has 0 fury, so all they have to do is fight you when your 0 fury and they'll win. really as you said, the key to doing well with him is to get an early kill to establish lane dominance than just farm farm and since you have lane control you'll be able to get fury up and punish your lane opponent with some crits.
On a side note about nasus, if you are even in kills and nasus is relatively close to your cs and has something like 75% of those cs as q farm, nasus won the lane, nasus is a monster late game and if he got really good q farm hes arguably the strongest champ in the game, but thats countered by the fact that his early game blows so to beat nasus you need to shut him down, but again tryn doesn't do this well.