Tryndamere is a champion that requires absolutely no skill,
It's more the other way around, Tryndamere feeds on players with no skill, making him a solid pick for your summoner level 1~30 adventures.
Once you get to a caliber of players Tryndamere requires a significant amount of skill to use passably well.
If you prevent him from building fury in lane, he automatically loses lane.
If you group for team fights, he tends to loose those too.
If you run at him 1 at a time, never group, and try to duel him while trying to max out your inventory slots with 6 completed items - then he's probably the best champion in the game.
Tryndamere is the least fun champion to play against in this game, hands down.
I'm not sure about least fun, but you're not exactly wrong in pointing this out. It's a core issue with a lot of fighter/assassins, especially those created at the start of LoL's history.
There shtick is basically winning 1v1 duels and stomping noobs. They're useless in team-fights without some massive defensive spike. This tends to cause them to do things like split-push to force 1v1s and refuse to group with their team, while catching a lot of players off-guard by easily mopping the floor with them in duels while using kit power to trump a lot of skill.